US20070290849A1 - System and Method for Locating Individuals and Equipment, Airline Reservation System, Communication System - Google Patents

System and Method for Locating Individuals and Equipment, Airline Reservation System, Communication System Download PDF

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Publication number
US20070290849A1
US20070290849A1 US11/845,706 US84570607A US2007290849A1 US 20070290849 A1 US20070290849 A1 US 20070290849A1 US 84570607 A US84570607 A US 84570607A US 2007290849 A1 US2007290849 A1 US 2007290849A1
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Prior art keywords
interrogator
antennas
interrogators
controller
antenna
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US11/845,706
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John Tuttle
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Round Rock Research LLC
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Keystone Technology Solutions LLC
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Priority to US11/845,706 priority Critical patent/US20070290849A1/en
Assigned to KEYSTONE TECHNOLOGY SOLUTIONS, LLC reassignment KEYSTONE TECHNOLOGY SOLUTIONS, LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MICRON TECHNOLOGY, INC.
Publication of US20070290849A1 publication Critical patent/US20070290849A1/en
Assigned to ROUND ROCK RESEARCH, LLC reassignment ROUND ROCK RESEARCH, LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MICRON TECHNOLOGY, INC.
Assigned to MICRON TECHNOLOGY, INC. reassignment MICRON TECHNOLOGY, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KEYSTONE TECHNOLOGY SOLUTIONS, LLC
Abandoned legal-status Critical Current

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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06KGRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K17/00Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06KGRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K17/00Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
    • G06K17/0022Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations arrangements or provisious for transferring data to distant stations, e.g. from a sensing device
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06QINFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q10/00Administration; Management
    • G06Q10/02Reservations, e.g. for tickets, services or events
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06QINFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q10/00Administration; Management
    • G06Q10/02Reservations, e.g. for tickets, services or events
    • G06Q10/025Coordination of plural reservations, e.g. plural trip segments, transportation combined with accommodation
    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07CTIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00Individual registration on entry or exit
    • G07C9/20Individual registration on entry or exit involving the use of a pass
    • G07C9/28Individual registration on entry or exit involving the use of a pass the pass enabling tracking or indicating presence
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B3/00Audible signalling systems; Audible personal calling systems
    • G08B3/10Audible signalling systems; Audible personal calling systems using electric transmission; using electromagnetic transmission
    • G08B3/1008Personal calling arrangements or devices, i.e. paging systems
    • G08B3/1016Personal calling arrangements or devices, i.e. paging systems using wireless transmission
    • G08B3/1083Pager locating systems
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B31/00Predictive alarm systems characterised by extrapolation or other computation using updated historic data
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/04Systems determining presence of a target
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M2242/00Special services or facilities
    • H04M2242/30Determination of the location of a subscriber

Definitions

  • the invention relates to personnel locating systems, travel reservation systems, airport security systems, radio frequency identification devices.
  • Travel reservation and baggage tracking systems are known in the art. Passengers typically purchase tickets in advance of travel, and are included in a database of a reservation system as having a reservation. On the date of travel, they must check in, or their seat will be given up to other passengers. Because statistics show that there will always be a number of passengers who will not show up on the designated date of travel, carriers typically “overbook” by selling a number of seats over the number of seats that are actually available, based on mathematical calculations. If the passenger does not check in, their seat may be used to accommodate overbooking, or may be given to standby passengers.
  • the following U.S. patents relate to reservation systems and are incorporated herein by reference: U.S. Pat. Nos. 5,401,944; 5,151,692; 5,051,565; 5,010,240; 4,984,156; 4,931,932; 4,449,186; 4,247,795; 3,750,103.
  • a passenger enters a travel depot e.g., an airport
  • they must therefore check in to make sure the carrier e.g., airline
  • the carrier e.g., airline
  • the employee receives the ticket and, using a reservation system, issues a boarding pass, with a seat assignment, indicating to the system that the seat is no longer available to be given away.
  • curbside check-in which allows a passenger to check in bags at the curb before entering the airport, where lines are shorter because a gratuity is expected.
  • the business travelers and travelers who have used the curbside check in typically go directly to the podium adjacent the departure gate and check in there. While the line at the podium may be shorter, it is still a line. Travelers needing to check in baggage must wait in lines.
  • airline staff may desire to make an attempt to determine if a checked in passenger is in the airport. It is also frequently desirable to locate airline staff, such as pilots, flight attendants, wheelchair attendants, mechanics etc., or airport staff, such as security, or merchants or other persons who work in airports, for a variety of reasons. This is presently attempted through paging, which is sometimes difficult to hear, and is often annoying or competing with more important messages, such as gate change announcements, or information about which rows are boarding.
  • the invention provides a system for locating an individual in a facility.
  • the system comprises a portable wireless transponder device borne by the individual; an interrogator; and a plurality of antennas distributed in the facility.
  • the antennas are selectively separately connected to the interrogator.
  • the interrogator when connected to any of the antennas has a communications range covering less than the area of the entire facility.
  • the interrogator repeatedly transmits a wireless command to the portable wireless transponder device using alternating antennas.
  • the portable wireless transponder device transmits data identifying the portable wireless transponder device in response to a command if the portable wireless transponder device is within communications range of the antenna sending the command.
  • the individual is located by determining with which antenna the interrogator was able to establish communications with the portable wireless transponder device.
  • FIG. 1 is a plan view of a travel depot facility, such as an airport, including a system, embodying the invention, for locating an individual.
  • FIG. 2 is a block diagram of the system of FIG. 1 , further including an interface with an airline reservation and baggage tracking system, and further including monitors for displaying information of particular interest to passengers in the area of the monitor.
  • FIG. 3 is a perspective view showing a monitor included in the system of FIG. 2 .
  • FIG. 4 is a front view of a card used in the system of FIG. 1 or 2 .
  • FIG. 5 is a circuit schematic of an interrogator included in the system of FIG. 1 or 2 .
  • FIG. 6 is a circuit schematic of circuitry included in card of FIG. 4 .
  • FIG. 7 is a block diagram of an interrogator included in the system of FIG. 1 or 2 .
  • FIG. 8 is a circuit schematic of DPSK circuitry included in the interrogator of FIG. 7 .
  • FIG. 9 is a circuit schematic of RF circuitry included in the interrogator of FIG. 7 .
  • FIG. 10 is a plan view of a card in accordance with an alternative embodiment of the invention.
  • FIG. 11 is a block diagram illustrating assembly of the card of FIG. 10 .
  • FIG. 12 is a flow chart illustrating a routine run by the system of FIG. 1 or 2 to log locations of individuals.
  • FIG. 13 is a flow chart illustrating a routine run by the system of FIG. 1 or 2 , used in connection with the routine of FIG. 12 , to determine the location of an individual.
  • FIG. 14 is a flow chart illustrating a routine run by the system of FIG. 2 to check in a passenger using the card of FIG. 4 or 10 as an electronic boarding pass.
  • FIG. 1 shows a travel depot facility 10 , such as an airport, including a system 12 (see FIG. 2 ) for locating an individual.
  • the facility 10 includes various areas of a typical facility such as a main terminal area 14 which typically includes a baggage check in area 16 , shops, restaurants, etc.
  • the facility 10 further includes a terminal concourse area 18 which one enters after passing a security check point 20 .
  • the terminal concourse area 18 includes multiple gate doors 22 defining controlled access points. More particularly, the gate doors 22 are typically locked until a flight is available for departure or is being deplaned. Airline staff control passage through the gate doors and only permit people with boarding passes through the gate doors 22 .
  • the gate doors 22 lead to jetways 24 which are movable to define a path into an airplane.
  • the terminal area 18 typically includes podiums 28 where airline personnel are located.
  • the terminal area 18 also includes multiple seating areas 30 which may be grouped off by gate.
  • the system 12 includes portable wireless transponder devices 32 borne by passengers, airport employees, contractors, airline and contractor employees, etc.
  • the devices 32 include circuitry such as the circuitry described in detail in commonly assigned U.S. patent application Ser. No. 08/705,043, filed Aug. 29, 1996, now U.S. Pat. No. 6,130,602, and incorporated herein by reference.
  • the portable transponder devices 32 have card shaped housings with length and width dimensions corresponding to standard length and width dimensions of credit cards.
  • the transponder devices 32 include photographs of the respective individuals associated with the devices.
  • the transponder devices 32 are, more particularly, intelligent radio frequency identification devices or remote intelligent communications (RIC) devices which communicate at microwave frequencies.
  • RIC remote intelligent communications
  • FIG. 4 shows but one example of a housing for a device 32 , in the form of an employee identification badge or card including an intelligent radio frequency identification device integrated circuit 34 .
  • the integrated circuit 34 includes a transmitter, a receiver, a microprocessor, and a memory.
  • the housing for the device 32 shown in FIG. 4 includes a card 36 made of plastic or other suitable material.
  • the integrated circuit 34 is laminated to the back face of the card 36 , and the card forms a visible portion of the badge.
  • the integrated circuit 34 is bonded to the back face of the card by embedding it within a thin bond line of epoxy-based material.
  • the integrated circuit 34 is embedded into the plastic card 36 .
  • the front face of the badge has visual identification features including a photograph 38 of the bearer as well as identifying text.
  • the device 32 further includes a send/receive antenna 40 coupled to the integrated circuit 34 , and a battery 42 coupled to the integrated circuit 34 to supply power to the integrated circuit.
  • the battery 42 and antenna 40 are embedded or supported inside the plastic card 36 .
  • the battery 42 can take any suitable form.
  • the battery type will be selected depending on weight, size, and life requirements for a particular application.
  • the battery 42 is a thin profile button-type cell forming a small, thin energy cell more commonly utilized in watches and small electronic devices requiring a thin profile.
  • a button-type cell has a pair of electrodes, an anode formed by one face and a cathode formed by an opposite face.
  • Exemplary button-type cells are disclosed in several pending U.S. patent applications including U.S. patent application Ser. No. 08/205,957, “Button-Type Battery Having Bendable Construction and Angled Button-Type Battery,” listing Mark E. Tuttle and Peter M. Blonsky as inventors, now U.S. Pat. No.
  • the battery 42 comprises a series connected pair of button type cells.
  • Alternative power supplies can be used instead of batteries, in alternative embodiments.
  • FIG. 5 illustrates but one alternative housing supporting the circuit 34 . More particularly, FIG. 5 illustrates a miniature housing 42 encasing the circuit 34 to define a tag which can be supported by a person or object.
  • the housing 42 preferably has the general shape and size, in plan view, of a postage stamp.
  • the embodiment of FIG. 5 also houses a card 44 supporting the circuit 34 in the housing 42 .
  • the card 44 is formed of plastic or other suitable material having a thickness of about 0.040 inches, a width of about 1.25 inches, and a height of about 1.25 inches.
  • the circuit 34 is bonded to a back face of the card 44 with a thin layer of non-conductive epoxy material that cooperates with the card to define the housing 42 .
  • the circuit 34 is coupled to a send antenna 48 , and a receive antenna 46 , and receives power from a battery 42 which can be similar to the battery included in the embodiment of FIG. 4 .
  • the battery 42 , and antennas 46 and 48 are supported in the housing 42 by the card 44 .
  • the circuit 34 can be included in any appropriate housing.
  • the circuit 34 is of a small size that lends itself to applications employing small housings, such as cards, miniature tags, etc. Larger housings can also be employed.
  • the circuit 34 housed in any appropriate housing, can be supported from a person, or attached to a object (or a peoples possessions) in any desired manner; for example using double sided tape, glue, lanyards, leash, nails, staples, rivets, or any other fastener.
  • the housing can be sewn on to an object, hung from an object, implanted in an object (hidden), etc.
  • the antenna connected to the circuit 34 may be Various configurations.
  • separate antennas 46 and 48 are provided for receiving and sending ( FIG. 5 ).
  • a single antenna 40 is shared by the receiver and transmitter ( FIG. 4 ).
  • one or more antennas are defined by conductive epoxy screened onto a card or housing. In the illustrated embodiment, the antenna is conductively bonded to the integrated circuit 34 via bonding pads.
  • the system 12 further includes an interrogator 50 .
  • the card 36 transmits and receives radio frequency communications to and from the interrogator 50 .
  • the system 12 further includes an array of antennas 52 (or send/receive antenna pairs) alternately coupled to the interrogator 50 .
  • the interrogator 50 includes transmitting and receiving circuitry, similar to that implemented in the circuit 34 .
  • the system 12 further includes a controller 54 .
  • the controller 54 is a computer.
  • the controller 54 acts as a master in a master-slave relationship with the interrogator 50 .
  • the controller 54 includes an applications program for controlling the interrogator 50 and interpreting responses, and a library of radio frequency identification device applications or functions. Most of the functions communicate with the interrogator 50 . These functions effect radio frequency communication between the interrogator 50 and the card 32 .
  • the controller 54 and the interrogator 50 are combined together (e.g., in a common housing), or functions of the host computer are implemented in hard wired digital logic circuitry.
  • the communications system 10 includes multiple selectable transmit antennas X 1 , X 2 , X 3 etc., and multiple receive antennas R 1 , R 2 , R 3 etc. connected to the interrogator 50 .
  • Each antenna pair X 1 , R 1 , X 2 , R 2 , etc. defines an antenna 52 of the antenna array for purposes of the discussion below.
  • the communications system 10 includes combined antennas that are used both for transmitting and receiving by the interrogator 50 .
  • the interrogator 50 transmits an interrogation signal or command, such as an “Identify” command, (“forward link”) via one of the antennas 52 .
  • the card 32 receives the incoming interrogation signal via its antenna, if it is within receiving range of the particular antenna 52 used to transmit. Upon receiving the signal, the card 32 responds by generating and transmitting a responsive signal or reply (“return link”).
  • the interrogator 50 is described in greater detail below.
  • the responsive signal is encoded with information that uniquely identifies, or labels the particular card 32 that is transmitting, so as to identify any object or person with which the card 32 is associated.
  • multiple cards 32 are employed; however, there is no communication between the cards 32 . Instead, the multiple cards 32 communicate with the interrogator 50 . Multiple cards 32 can be used in the same range of an antenna 52 .
  • Radio Frequency Identification Device RFID
  • Method of Manufacture Including an Electrical Operating System and Method
  • Ser. No. 07/151,599 filed Nov. 12, 1993, now U.S. Pat. No. 5,406,263, “Anti-Theft Method for Detecting The Unauthorized Opening of Containers and Baggage,”
  • Ser. No. 07/168,909 filed Dec. 17, 1993, now U.S. Pat. No. 5,497,140, “Electrically Powered Postage Stamp or Mailing or Shipping Label Operative with Radio Frequency (RF) Communication”
  • Ser. No. 08/032,384 filed on Mar. 17, 1993, “Modulated Spread Spectrum in RF Identification Systems Method,” now allowed.
  • the integrated circuit 34 is advantageous over prior art devices that utilize magnetic field effect systems because, with the circuit 34 , a greater range can be achieved, and more information can be obtained (instead of just an identification number). As a result, the circuit 34 can be used for the application of the present invention, where transmission over a large range is required.
  • the sensitivity of the cards 32 is adjustable so that only devices within an adjustable range of an antenna 52 will respond.
  • the power of the interrogator 50 is adjustable so that only devices within a certain range of an antenna 52 will respond.
  • a power conservation problem is posed by such implementations where batteries are used to supply power to the integrated circuits 34 . If the integrated circuit 34 operates continuously at full power, battery life will be short, and card 32 will have to be frequently replaced. If the battery 42 is permanently sealed in a housing, replacement of the battery will be difficult or impossible. For example, one reason for sealing the battery with the integrated circuit 34 and antenna(s) in a housing is to simplify the design and construction, to reduce the cost of production, and protect the electrical interconnections between devices. Another reason is protection of the battery and integrated circuit 34 from moisture and contaminants. A third reason is to enhance the cosmetic appeal of the card 32 by eliminating the need for an access port or door otherwise necessary to insert and remove the battery. When the battery is discharged, the entire badge or stamp is then discarded. It is therefore desirable to incorporate power conservation techniques into the integrated circuit 32 in order to extend useful life.
  • FIG. 6 is a circuit schematic of the integrated circuit 34 utilized in the devices of FIG. 4 or 5 .
  • the circuit 34 is a monolithic integrated circuit.
  • the integrated circuit 34 comprises a single die, having a size of 209 ⁇ 116 mils 2 .
  • the integrated circuit 34 includes a receiver 56 , a transmitter 58 , a micro controller or microprocessor 60 , a wake up timer and logic circuit 62 , a clock recovery and data recovery circuit 64 , and a bias voltage and current generator 66 .
  • the circuit 34 switches between a “sleep” mode of operation, and higher power modes to conserve energy and extend battery life during periods of time where no interrogation signal is received by the circuit 34 .
  • the wake up timer and logic circuitry 62 provides this switching.
  • a spread spectrum processing circuit 68 is also included in the circuit 34 .
  • signals transmitted and received by the interrogator 50 , and signals transmitted and received by the circuit 34 are modulated spread spectrum signals.
  • Spread spectrum modulation is described below.
  • the modulation scheme for replies sent by the transmitter 58 is selectable.
  • One of the available selections for replies sent by the transmitter 58 is modulated spread spectrum.
  • the spread spectrum modulation technique employed in the illustrated embodiment requires a transmission bandwidth that is up to several orders of magnitude greater than the minimum required signal bandwidth.
  • spread spectrum modulation techniques are bandwidth inefficient in single user applications, they are advantageous where there are multiple users, as is the case with the instant circuit 34 .
  • the spread spectrum modulation technique of the illustrated embodiment is advantageous because the interrogator signal can be distinguished from other signals (e.g., radar, microwave ovens, etc.) operating at the same frequency.
  • the spread spectrum signals transmitted by the circuit 34 and by the interrogator 50 are pseudo random and have noise-like properties when compared with the digital command or reply.
  • the spreading waveform is controlled by a pseudo-noise or pseudo random number (PN) sequence or code.
  • the PN code is a binary sequence that appears random but can be reproduced in a predetermined manner by the circuit 34 . More particularly, incoming spread spectrum signals are demodulated by the circuit 34 or by the interrogator 50 through cross correlation with a version of the pseudo random carrier that is generated by the circuit 34 itself or the interrogator 50 itself, respectfully. Cross correlation with the correct PN sequence unspreads the spread spectrum signal and restores the modulated message in the same narrow band as the original data.
  • a pseudo-noise or pseudo random sequence is a binary sequence with an autocorrelation that resembles, over a period, the autocorrelation of a random binary sequence.
  • the autocorrelation of a pseudo-noise sequence also roughly resembles the autocorrelation of band-limited white noise.
  • a pseudo-noise sequence has many characteristics that are similar to those of random binary sequences. For example, a pseudo-noise sequence has a nearly equal number of zeros and ones, very low correlation between shifted versions of the sequence, and very low cross correlation between any two sequences.
  • a pseudo-noise sequence is usually generated using sequential logic circuits. For example, a pseudo-noise sequence can be generated using a feedback shift register.
  • a feedback shift register comprises consecutive stages of two state memory devices, and feedback logic. Binary sequences are shifted through the shift registers in response to clock pulses, and the output of the various stages are logically combined and fed back as the input to the first stage. The initial contents of the memory stages and the feedback logic circuit determine the successive contents of the memory.
  • the illustrated embodiment employs direct sequence spread spectrum modulation.
  • a direct sequence spread spectrum (DSSS) system spreads the baseband data by directly multiplying the baseband data pulses with a pseudo-noise sequence that is produced by a pseudo-noise generator.
  • a single pulse or symbol of the PN waveform is called a “chip.”
  • Synchronized data symbols which may be information bits or binary channel code symbols, are added in modulo-2 fashion to the chips before being modulated.
  • the receiver performs demodulation.
  • the data is phase modulated, and the receiver performs coherent or differentially coherent phase-shift keying (PSK) demodulation.
  • PSK phase-shift keying
  • the data is amplitude modulated. Assuming that code synchronization has been achieved at the receiver, the received signal passes through a wideband filter and is multiplied by a local replica of the PN code sequence. This multiplication yields the unspread signal.
  • a pseudo-noise sequence is usually an odd number of chips long.
  • one bit of data is represented by a thirty-one chip sequence.
  • a zero bit of data is represented by inverting the pseudo-noise sequence.
  • the interrogator 50 sends out a command that is spread around a certain center frequency (e.g., 2.44 GHz). After the interrogator transmits the command, and is expecting a response, the interrogator switches to a CW mode (continuous wave mode). In the continuous wave mode, the interrogator does not transmit any information. Instead, the interrogator just transmits 2.44 GHz radiation. In other words, the signal transmitted by the interrogator is not modulated. After the circuit 34 receives the command from the interrogator, the circuit 34 processes the command. If the circuit 34 is in a backscatter mode it alternately reflects or does not reflect the signal from the interrogator to send its reply. For example, in the illustrated embodiment, two halves of a dipole antenna are either shorted together or isolated from each other to send a reply.
  • a certain center frequency e.g., 2.44 GHz
  • Frequency hopping is employed in one embodiment.
  • frequency hopping does not occur when the interrogator transmits a command, but occurs when the interrogator is in the continuous wave mode.
  • the interrogator in the continuous wave mode, hops between various frequencies close to the 2.44 GHz frequency. These various frequencies are sufficiently close to the 2.44 GHz frequency that backscatter antenna reflection characteristics of the circuit 34 are not appreciably altered. Because the interrogator is hopping between frequencies, the interrogator knows what frequency backscatter reflections to expect back from the circuit 34 . By hopping between various frequencies, the amount of time the interrogator continuously uses a single frequency is reduced. This is advantageous in view of FCC regulatory requirements.
  • no attempt is made to frequency hop at the interrogator to a pseudo-random sequence and then correlate to that at the receiver.
  • such correlation takes place.
  • the transmitter 58 is switchable between operating in a modulated backscatter transmitter mode, and operating in an active mode.
  • the transmitter 58 switches between the backscatter mode and the active mode in response to a radio frequency command, instructing the transmitter to switch, sent by the interrogator 50 and received by the receiver 56 .
  • a carrier for the transmitter 58 is extracted from a signal received by the receiver 56 .
  • Active transmitters are known in the art. See, for example, U.S. patent application Ser. No. 08/281,384; U.S. patent application Ser. No. 08/281,384 also discloses how transmit frequency for the transmitter 58 is recovered from a message received via radio frequency from the interrogator 50 .
  • the transmitter 58 is capable of transmitting using different modulation schemes, and the modulation scheme is selectable by the interrogator. More particularly, if it is desired to change the modulation scheme, the interrogator sends an appropriate command via radio frequency.
  • the transmitter can switch between multiple available modulation schemes such as Binary Phase Shift Keying (BPSK), Direct Sequence Spread Spectrum, On-Off Keying (OOK), and Modulated Backscatter (MBS).
  • BPSK Binary Phase Shift Keying
  • OOK On-Off Keying
  • MFS Modulated Backscatter
  • the clock for the entire integrated circuit 16 is extracted from the incoming message itself by clock recovery and data recovery circuitry 64 .
  • This clock is recovered from the incoming message, and used for timing for the micro controller 60 and all the other clock circuitry on the chip, and also for deriving the transmitter carrier or the subcarrier, depending on whether the transmitter is operating in active mode or backscatter mode.
  • the clock recovery and data recovery circuit 64 also performs data recovery on valid incoming signals.
  • the valid spread spectrum incoming signal is passed through the spread spectrum processing circuit 68 , and the spread spectrum processing circuit 68 extracts the actual ones and zeros of data from the incoming signal. More particularly, the spread spectrum processing circuit 68 takes the chips from the spread spectrum signal, and reduces each thirty-one chip section down to a bit of one or zero, which is passed to the micro controller 60 .
  • the micro controller 60 includes a serial processor, or I/O facility that received the bits from the spread spectrum processing circuit 68 .
  • the micro controller 60 performs further error correction. More particularly, a modified hamming code is employed, where each eight bits of data is accompanied by five check bits used by the micro controller 60 for error correction.
  • the micro controller 60 further includes a memory, and after performing the data correction, the micro controller 60 stores bytes of the data bits in memory. These bytes contain a command sent by the interrogator 50 . The micro controller 60 responds to the command.
  • the interrogator 50 may send a command over one of the antennas 52 requesting that any integrated circuit 34 in communications range of that antenna 52 respond with the integrated circuit's identification number. Status information is also returned to the interrogator 50 from the integrated circuit 34 when the circuit 34 responds.
  • the transmitted replies have a format similar to the format of incoming messages. More particularly, a reply starts with a preamble (e.g., all zeros in active mode, or alternating double zeros and double ones in backscatter mode), followed by a Barker or start code which is thirteen bits long, followed by actual data.
  • a preamble e.g., all zeros in active mode, or alternating double zeros and double ones in backscatter mode
  • Barker or start code which is thirteen bits long, followed by actual data.
  • No stop bits are included in the incoming message or reply, in the preferred embodiment. Instead, part of the incoming message describes how many bytes are included, so the integrated circuit 34 knows how much information is included. Similarly, part of the outgoing reply describes how many bytes are included, so the interrogator 50 knows how much information is included.
  • the incoming message and outgoing reply preferably also include a check sum or redundancy code so that the integrated circuit 34 or the interrogator 50 can confirm receipt of the entire message or reply.
  • the integrated circuit 34 After the reply is sent, the integrated circuit 34 returns to the sleep mode, and the wake up timer and logic circuit 62 starts timing again for the next wake up (e.g., in 16 milliseconds, or whatever period is selected).
  • the interrogator 50 provides a communication link between the controller 54 and the integrated circuit 34 .
  • the interrogator 50 connects to the controller 54 via an IEEE-1284 enhanced parallel port (EPP).
  • EPP enhanced parallel port
  • the interrogator communicates with the circuit 34 via a selected RF (microwave) antenna 52 .
  • communications from the interrogator 50 to the circuit 34 , and communications from the circuit 34 to the interrogator 50 use different physical protocols.
  • the physical communications protocol for communications from the interrogator 50 to the circuit 34 is referred to as the “forward link” protocol.
  • the forward link data is sent in the following order:
  • PN Sequence is used in the Direct Sequence Spread Spectrum (DSSS) communications scheme in the forward link.
  • the sequence is generated by a linear feedback shift register of the form [5,2]. That is, there are five registers, the output of the second register is X-ORed with the output of the fifth register, and the result is fed into the input of the first register one. This produces a repeating 31 “chip” sequence. The sequence ends with all registers set to one. The sequence is taken from the output of the first register. This code is synchronous with the data in that each data bit comprises one and only one full PN sequence.
  • the chip sequence for each bit is:
  • a zero bit is transmitted as one inverted full cycle of the PN sequence.
  • a one bit is transmitted as one full non-inverted cycle of the PN sequence.
  • the data is not differentially encoded.
  • One rate is 9.5375 Mchips/sec (high band) and another rate is 4.768750 Mchips/sec (low band).
  • the preamble precedes the data.
  • the preamble includes a series of zeros, followed by a start or Barker code.
  • the preamble includes a series of zeros for a duration equal to the wakeup interval (e.g., 5, 16, 64, or 256 ms) plus 2 milliseconds, followed by a start or Barker code.
  • the Barker code is defined by the following bit string:
  • Command data is grouped into 13-bit words.
  • Each word includes eight data bits (D 7 , D 6 , D 5 , D 4 , D 3 , D 2 , D 1 , D 0 ) and five ECC (Error Correction Code) bits (P 4 , P 3 , P 2 , P 1 , and P 0 ).
  • ECC Error Correction Code
  • the bit transmission order is (with D 7 transmitted first):
  • Data rates depend on which data band is being used.
  • a high data band has an effective data rate (adjusting for PN and ECC) of 189.3 Kbps.
  • a low data band has an effective data rate of 94.68 Kbps.
  • a 16-bit check sum is provided to detect bit errors on the packet level.
  • a circuit 34 can be programmed to either return a reply if a bad check sum is found in the forward link, or to simply halt execution and send no replies.
  • a 16 bit CRC is employed in the forward link, the return link, or both, instead of or in addition to the check sum.
  • the physical communications protocol for communications from the circuit 34 to the interrogator 50 is referred to as the “return link” protocol.
  • the return link messages are sent in the following order:
  • the interrogator After sending a command, the interrogator sends a continuous unmodulated RF signal with a frequency of 2.44175; Ghz.
  • Return link data is Differential Phase Shift Key (DPSK) modulated onto a square wave subcarrier with a frequency of 596.1 Khz.
  • a data 0 corresponds to one phase and data 1 corresponds to another, shifted 180 degrees from the first phase.
  • the subcarrier is used to modulate antenna impedance of a card 32 .
  • a switch between the two halves of the dipole antenna is opened and closed. When the switch is closed, the antenna becomes the electrical equivalent of a single half-wavelength antenna that reflects a portion of the power being transmitted by the interrogator.
  • antennas 52 are located no more than 15 feet apart in areas of the facility 10 where it is desirable to locate people or objects.
  • the preamble for the return link includes 2000 bits, alternating 2 zeros then 2 ones, etc., and a 13-bit start (Barker) code. Alternative preambles are possible.
  • the start code or Barker Code is defined by the following bit string: 1111 1001 1010 1.
  • the reply link data is grouped in 13 bit words. Each word is composed of 8 data bits (D 7 , D 6 , D 5 , D 4 , D 3 , D 2 , D 1 , D 0 ) and 5 ECC bits (P 4 , P 3 , P 2 , P 1 , P 0 ).
  • the Block Encoded Sequence is D 7 , D 6 , D 5 , D 4 , D 3 , D 2 , D 1 , D 0 , P 4 , P 3 , P 2 , P 1 , P 0 .
  • the bit duration is 6.71 ⁇ s making the effective data rate 91.75 Kbps for the return link.
  • a 16-bit check sum is provided to detect bit errors on the packet level.
  • a 16 bit CRC is employed in addition to or instead of the check sum.
  • Each pair of data words is interleaved, starting with the Barker code and the first data word.
  • the transmitted bit order for two sequential words, A and B is D 7 A, D 7 B, D 6 A, D 6 B, D 5 A, D 5 B, D 4 A, D 4 B, D 3 A, D 3 B, D 2 A, D 2 B, D 1 A, D 1 B, D 0 A, D 0 B, P 4 A, P 4 B, P 3 A, P 3 B, P 2 A, P 2 B, P 1 A, P 1 B, P 0 A, P 0 B.
  • D 7 A is the first transmitted bit.
  • DPSK is applied to the interleaved data.
  • the interrogator 50 includes enhanced parallel port (EPP) circuitry 70 , DPSK (differential phase shift keyed) circuitry 72 , and RF (radio frequency) circuitry 74 , as well as a power supply (not shown) and a housing or chassis (not shown).
  • EPP enhanced parallel port
  • DPSK differential phase shift keyed
  • RF radio frequency
  • the enhanced parallel port circuitry 70 , the DPSK circuitry 72 , and the RF circuitry 74 respectively define circuit card assemblies (CCAs).
  • the interrogator uses an IEEE-1284 compatible port in EPP mode to communicate with the controller 54 .
  • the EPP circuitry 70 provides all the digital logic required to coordinate sending and receiving a message to and from a circuit 34 .
  • the EPP circuitry 70 buffers data to transmit from the controller 54 , converts the data to serial data, and encodes it. The EPP circuitry 70 then waits for data from the circuit 34 , converts it to parallel data, and transfers it to the controller 54 .
  • messages include up to 64 bytes of data.
  • the EPP mode interface provides an asynchronous, interlocked, byte wide, bidirectional channel controlled by the controller 54 .
  • the EPP mode allows the controller 54 to transfer, at high speed, a data byte to/from the interrogator within a single host computer CPU I/O cycle (typically 0.5 microseconds per byte).
  • the DPSK circuitry 72 receives signals I and Q from the RF circuitry 74 (described below), which signals contain the DPSK modulated sub-carrier.
  • the DPSK circuitry 72 includes anti-aliasing filters 76 and 78 filtering the I and Q signals, respectively, and analog to digital (A/D) converters 80 and 82 respectively coupled to the filters 76 and 78 and respectively converting the filtered signals from analog to digital signals.
  • the DPSK circuitry 72 further includes a combiner 84 , coupled to the A/D converters 80 and 82 , combining the digital signals.
  • the DPSK circuitry 72 further includes a FIR matched filter 86 , coupled to the combiner 84 , which filters the combined signals.
  • the DPSK circuitry 72 further includes delay circuitry 88 and multiplier circuitry 90 coupled to the FIR matched filter 86 for delaying the signal and multiplying the signal with the delayed signal to remove the sub-carrier.
  • the DPSK circuitry 72 further includes low pass filter circuitry 92 , coupled to the multiplier 90 , filtering the output of the multiplier 90 to remove the X 2 component.
  • the DPSK circuitry 72 further includes a bit synchronizer 94 coupled to the filter 92 for regeneration of the data clock.
  • the DPSK circuitry 72 further includes lock detect circuitry 96 coupled to the low pass filter 92 and generating a lock detect signal. The data, clock, and lock detect signal are sent to the EPP circuitry 70 .
  • the RF circuitry 74 (see FIG. 9 ) interfaces with the transmit and receive antennas X 1 , X 2 , X 3 , etc., and R 1 , R 2 , R 3 , etc defining antennas 52 .
  • the RF circuitry modulates the data for transmission to a circuit 34 , provides a continuous wave (CW) carrier for backscatter communications with a circuit 34 (if backscatter communications are employed), and receives and downconverts the signal received from the transponder unit (which is a backscatter signal in one embodiment).
  • CW continuous wave
  • the RF circuitry 74 also includes a power divider 98 , and a frequency synthesizer 100 coupled to the power divider 98 .
  • the frequency synthesizer 100 tunes the RF continuous waver carrier for frequency hopping and band selection.
  • the RF circuitry defines a transmitter, and receives data from the EPP circuitry 70 .
  • the RF circuitry 74 includes an amplitude modulation (AM) switch 102 that receives the data from the EPP circuitry 70 and amplitude modulates the data onto a carrier. More particularly, the AM switch 102 turns the RF on and off (ON OFF KEY).
  • the RF circuitry 74 further includes a power amplifier 104 , coupled to the AM switch 102 , to amplify the signal.
  • the RF circuitry 74 further includes a switch 106 , coupled to the power amplifier 104 , for transmission of the amplified signal through a selected one of the transmit antennas X 1 , X 2 , X 3 ,
  • the AM switch 102 is left in a closed position.
  • the circuit 34 backscatters the signal with a DPSK modulated sub carrier. This signal is received via one of the receive antennas R 1 , R 2 , R 3 , etc.
  • the RF circuitry 74 further includes a switch 108 coupled to the receive antennas R 1 , R 2 , R 3 , etc.
  • the RF circuitry uses common antennas for both transmission and reception, and alternates use of antennas from multiple available send/receive antennas.
  • the RF circuitry 74 further includes a low noise amplifier (LNA) 110 coupled to the switch 108 and amplifying the received signal.
  • the RF circuitry 74 further includes a quadrature downconverter 112 , coupled to the LNA 110 , coherently downconverting the received signal.
  • the RF circuitry 74 further includes automatic gain controls (AGCs) 114 and 116 coupled to the quadrature down converter 112 . The amplitude of the signals are set using the automatic gain controls 114 and 116 to provide the signals I and Q.
  • the I and Q signals which contain the DPSK modulated sub-carrier, are passed on to the DPSK circuitry 72 ( FIG. 8 ) for demodulation.
  • interrogator 50 Although one interrogator 50 has been described, it may be desirable to provide multiple interrogators depending on the size and layout of a facility, in which case the multiple interrogators will preferably share information.
  • the interrogator or interrogators 50 are respectively selectively connected to the antennas 52 of an array of antennas distributed in at least the passenger areas of the facility, such as in the main terminal 14 , the baggage check in area 16 , the terminal concourse area 18 , and the security check area 20 .
  • An interrogator connected to any of the antennas 52 has a range covering less than the area of the entire facility 10 . More particularly, the more antennas 52 that are provided, the more precisely the location of an individual can be determined (the transmission and reception range of the interrogator can be decreased appropriately).
  • some antennas 52 are located in non-passenger areas, such as outdoor areas, to assist in locating individuals or equipment instead of passengers.
  • the antennas 52 are designed for transmission and reception at microwave frequencies (e.g., 2.44 GHz). As described above, the antennas 52 can either comprise combined send/receive antennas, or separate antennas for sending (transmitting) and receiving. If separate antennas are used for sending and receiving, they will be referred to as a single antenna for purposes of the following discussion and claims.
  • the antennas 52 are distributed fairly evenly throughout monitored areas of the facility 10 .
  • an area of communication is defined by the interrogator 50 connected to an antenna 52 , and the area of communication of the interrogator using one of the antennas 52 overlaps with the area of communication of the interrogator using another one of the antennas 52 so that there are no gaps in the areas of the facility desired to be covered by the system.
  • the interrogator 52 repeatedly transmits a wireless command to the portable wireless transponder device using alternating ones of the antennas 52 .
  • the interrogator is sequentially connected to respective antennas 52 , and makes at least one communication attempt using each antenna 52 .
  • the device 32 owned by an individual or supported by an object or checked or carry-on luggage transmits data identifying the device 32 (and thus the bearer or possessor of the device 32 ) in response to an interrogator command if the device 32 is within communications range of the antenna 52 sending the command.
  • the individual or object is located by determining with which antenna the interrogator 50 was able to establish communications with the portable wireless transponder device.
  • FIGS. 12 and 13 illustrate routines executed by the controller 54 to locate individuals, equipment, or checked or carry-on baggage in the facility 10 .
  • a piece of carry on baggage becomes separated from its owner for a predetermined time, an assumption can be made that it is either lost or else creates a possible bomb risk that should be investigated.
  • the system can be used to locate a passenger's lost carry on or checked baggage.
  • the routine of FIG. 12 is continuously run (during hours of operation of the facility) and includes a step 118 of causing the interrogator to send an “identify” command, which requests that all devices 32 (within communication range) reply with their respective identification numbers. After performing step 118 , the controller 54 proceeds to step 120 .
  • step 120 the controller 54 deletes old entries and logs identification numbers of devices 32 within the range of the antenna 52 being used. After performing step 120 , the controller 54 proceeds to step 122 .
  • step 122 the controller switches the antenna 52 (or antenna pair) being used by the interrogator. After performing step 122 , the controller 54 proceeds to step 118 .
  • the routine of FIG. 13 is run when it is desired to locate a specific individual, item of equipment, piece of carry-on baggage, or piece of checked baggage (by inputting an identification number of a device 32 ).
  • the routine of FIG. 13 includes a step 124 of receiving (inputting) an inquiry as to the location of a particular individual. After performing step 124 , the controller 54 proceeds to step 126 .
  • step 126 the controller determines if the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) is on the carrier (plane) by checking the logs for antennas at controlled access points (e.g., the gate for the flight the individual was scheduled to take). After performing step 126 , the system proceeds to step 128 .
  • step 128 a determination is made as to whether the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) is on the carrier. If so, the controller proceeds to step 130 . If not, the controller proceeds to step 132 .
  • step 130 the location of the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) is displayed as being on board the carrier (e.g. the airplane). After performing step 130 , execution terminates.
  • steps 132 and 134 (which can be combined), current (most recent) logs are read for all other antennas, and the controller searches for the particular individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) in these logs. After performing steps 132 and 134 , the controller proceeds to step 136 .
  • step 136 a determination is made as to whether the particular individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) was located in any of these logs. If so, the controller proceeds to step 140 . If not, the controller proceeds to step 138 .
  • step 138 the controller causes a display to be generated that the search failed or the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) was not located on the premises. After performing step 138 , execution terminates.
  • step 140 a determination is made as to whether the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) was located in more than one log in logs associated with more than one antenna). If so, the controller proceeds to step 142 . If not, the controller proceeds to step 144 .
  • step 142 the location is displayed of the antenna where the logged communication with the device of the particular individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) took place. This is presumably where the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) is presently located.
  • step 144 because the individual has been logged in more than one antenna location, all antenna locations can be displayed or, in the illustrated embodiment, triangulation or telemetry are used, and/or relative signal strengths measured by the multiple antennas for the last logged reply by the card are used, to locate with particularity the particular individual's location (or the location of the item of equipment, or piece of carry-on baggage, or piece of checked baggage).
  • the direction of travel is also determined by determining change in triangulated location with respect to time.
  • step 146 the controller causes the location of the particular individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) to be displayed. After performing step 146 , the controller proceeds to step 148 .
  • This system and routine can be used to track the location of equipment bearing the circuit 34 , carry-on baggage bearing the equipment, or checked baggage bearing the equipment.
  • the system 12 further comprises a carrier (e.g., airline) reservation and baggage tracking system 152 ( FIG. 2 ).
  • a carrier e.g., airline
  • Any presently used reservation system can be employed.
  • a system such as the systems described in incorporated U.S. Pat. Nos. 5,401,944; 5,151,692; 5,051,565; 5,010,240; 4,984,156; 4,931,932; 4,449,186; 4,247,795; and 3,750,103 can be employed for the carrier reservation and baggage tracking system 152 .
  • the reservation and baggage tracking system 152 includes a computer having a database storing information identifying passengers who have purchased tickets for passage (e.g., a flight), information about scheduled departures (e.g., for flights), information identifying passengers who have checked in (e.g., for a flight), etc.
  • the system 12 further includes a network 154 connecting the interrogator 50 to the carrier reservation and baggage tracking system 152 .
  • Any appropriate network such as a local area network, wide area network, Intranet network, Internet network, etc. can be employed. If multiple airlines or carriers in the facility have separate reservation systems, the network 154 preferably connects all participating reservation systems to the interrogator 50 .
  • the card 32 is used to automatically check in a passenger who enters the facility or a designated area of the facility (e.g., a gate area), as desired.
  • the interrogator 50 defines a wireless transponder in communication with the computer of the carrier reservation and baggage tracking system 152 .
  • the interrogator periodically sends wireless commands requesting responses from portable identification devices (e.g., the cards 32 ).
  • the cards 32 transmitting identifying data (e.g., a serial number that is associated with the bearer, a Social Security Number, a frequent flyer number, a confirmation number, etc.) in response to receiving a command from the interrogator.
  • the interrogator has a desired coverage area (e.g., in the airport, or in the gate area), and communicates only with cards 32 within the desired area.
  • the computer of the carrier reservation and baggage tracking system 152 modifies the reservation database to indicate that a passenger has checked in, in response to the interrogator 50 receiving a response from a card 32 in the desired coverage area.
  • the card 32 acts as an electronic boarding pass, saving the passenger from having to stand in line to check in, and reducing labor required by the carrier.
  • the electronic boarding pass (card 32 ) is accepted to check in a passenger only within a predetermined time period before a scheduled departure.
  • the electronic boarding pass is only accepted if the response from the card 32 includes identifying data for a passenger for whom the database in the carrier reservation and baggage tracking system 152 indicates that a ticket for a flight has been purchased.
  • a routine for execution by the system 152 to this effect is provided in FIG.
  • step 156 the system 152 retrieves a list of passengers having reservations for flights scheduled to leave in the next predetermined time period (e.g., flights scheduled to leave in the next two hours, or next one hour). After performing step 156 , the system proceeds to step 158 .
  • a predetermined time period e.g., flights scheduled to leave in the next two hours, or next one hour.
  • step 158 a determination is made as to whether identification data (e.g., Social Security Number, frequent flier number, serial number, etc.) logged using designated antennas 52 (e.g., in the airport, or in the gate area for the particular flight, etc.) match the identification data of any passengers on the reservation list for flights scheduled to leave in the next predetermined time period. If so, the system proceeds to step 160 . If not, the system proceeds to step 162 .
  • identification data e.g., Social Security Number, frequent flier number, serial number, etc.
  • step 160 the system checks in the qualifying passengers (those logged using designated antennas and matching the identification data of passengers on the reservation list for flights scheduled to leave in the next predetermined time period). The system further assigns seats (this may be based on known customer preferences, such as preferences stored for frequent fliers), and moves the checked in passengers from the reservation list to the checked in list. This is so that there is no need to search for passengers who have already checked in, next time step 156 is executed. After performing step 160 , the system proceeds to step 166 .
  • step 162 a time delay is imposed so that the system is freed up to perform other tasks. After performing step 162 , the system proceeds to step 164 .
  • step 164 the time is updated. In other words, the system time is retrieved for purposes of defining the predetermined time period of step 156 . After performing step 164 , the system proceeds to step 156 .
  • step 166 a time delay is imposed so that the system is freed up to perform other tasks. After performing step 166 , the system proceeds to step 168 .
  • step 168 the time is updated. In other words, the system time is retrieved for purposes of defining the predetermined time period of step 156 . After performing step 168 , the system proceeds to step 156 .
  • the transponder device 32 is manufactured using techniques such as those described in a commonly assigned U.S. patent application (attorney docket MI40-048) titled “Tamper Resistant Smart Card and Method of Protecting Data In a Smart Card”, filed Feb. 13, 1997, listing as inventor John R. Tuttle et al., now U.S. Pat. No. 5,988,510, and incorporated herein by reference.
  • the device 32 includes a magnetic stripe which the carrier (e.g., airline) can use for various purposes instead of or in addition to using the antennas 42 .
  • an airline may use the antennas 42 to check in a passenger, but may use the magnetic stripe with a card reader at a gate 22 (such as the card reader described in U.S. Pat. No. 5,010,240) in place of a boarding card when a passenger passes through the gate 22 to board a plane, or vice versa.
  • a card reader at a gate 22 such as the card reader described in U.S. Pat. No. 5,010,240
  • the system gives an indication to a passenger that the passenger has been successfully checked in, such as by displaying a message on a monitor, on a display on the card 32 (described elsewhere herein), by making an announcement on a speaker, or by other means.
  • a similar method and routine is used to check in luggage bearing a card 32 (or a miniature tag housing the integrated circuit 34 ) which is configured to transmit data indicating the card is associated with checked baggage (instead of carry-on baggage or other equipment) in response to a command from the interrogator.
  • the luggage can be checked in instead of or, preferably, in addition to the passenger. This way, the passenger can just leave the luggage in a designated area instead of waiting in a line. Airline personnel can determine the destination by interrogating the card 32 or tag on the baggage. Thus, the card 32 or tag becomes an electronic (recyclable) baggage tag.
  • the card 32 or tag on the checked baggage includes a display (as described elsewhere herein), which displays the destination of the baggage (and/or transfer points).
  • the system 12 communicates custom travel (e.g. flight) information to a passenger.
  • the system 12 uses the computer of the previously described carrier reservation and baggage tracking system 152 .
  • the system further includes monitors 170 and/or speakers 172 , and appropriate converters 174 and 176 connecting the monitors and speakers to the network.
  • the converters 174 may convert from EGA, VGA, or super VGA to a standard television signal, and the converters 176 , for example, may be sound cards or equivalent circuitry.
  • the interrogator 50 determines this in the same way that the interrogator 50 locates passengers, by communicating with a card 32 possessed by the passenger.
  • the system accesses the reservation and baggage tracking system 152 , retrieves the departure information for that passenger, and displays the information on the monitor as shown in FIG. 3 . More particularly, the system uses the existing reservation database of the system 152 , including information identifying passengers who have purchased tickets for a flight, and information about scheduled departures.
  • the information includes existing information such as a flight, bus or train number 178 , destination 180 , a gate, bay, or track number 182 , scheduled departure time 184 , and status information 186 (e.g., boarding, on time, delayed, gate change, see agent, cancelled, etc.).
  • existing information such as a flight, bus or train number 178 , destination 180 , a gate, bay, or track number 182 , scheduled departure time 184 , and status information 186 (e.g., boarding, on time, delayed, gate change, see agent, cancelled, etc.).
  • the information displayed therefore preferably includes the passenger's name 188 (or an identifying code or number known by the passenger), as well.
  • the information may be sorted (arranged) by passenger name in alphabetical order, by scheduled departure time, or by order of detection of the passengers by the interrogator 50 .
  • an alternative card 32 B is provided which is similar to the card 32 , but further includes a display 190 coupled to the integrated circuit 34 .
  • the display 190 can be a liquid crystal display, LED display, or other type of display.
  • the customized information for the passenger bearing the card 32 B appears on the display 190 .
  • the display 190 can be activated by bringing the card 32 B in communication range with a designated antenna 52 in the facility (which may be arranged to have a small range requiring close proximity, so the display is not continuously activated while the passenger travels through the facility).
  • the card 32 B is further include an actuator 192 coupled to the integrated circuit 34 , actuation of which causes display of the information.
  • the information can be similar to the information displayed on the monitor 170 , if a monitor 170 is used, except that the name of the passenger may be omitted because the bearer of the card 32 B is obviously the passenger. On the other hand, it may be desirable to display the passenger name to avoid mistaken swapping of the cards 32 B or to avoid theft.
  • the actuator 192 may be connected to an analog or digital input pin of the integrated circuit.
  • the card further includes a buffer memory 194 coupled to a serial input/output port of the integrated circuit 34 , a controller 196 , and a display driver 198 .
  • the serial input output port is used to load the buffer memory 194 , and then the controller 196 and display driver 198 drive the display 190 .
  • systems of multiple facilities are connected together, such as by using a telephone link, wide area network, Internet, Intranet, etc., so that data can be shared among various systems.
  • the location of checked luggage, carry-on luggage, equipment, or individuals can be determined if the location is within communications range of an interrogator in any of the connected facilities (airports).

Abstract

A system for locating an individual in a facility, the system comprising a portable wireless transponder device borne by the individual; an interrogator; and a plurality of antennas distributed in the facility, the antennas being selectively separately connected to the interrogator, the interrogator when connected to any of the antennas having a communications range covering less than the area of the entire facility, the interrogator being configured to repeatedly transmit a wireless command to the portable wireless transponder device using alternating antennas, the portable wireless transponder device being configured to transmit data identifying the portable wireless transponder device in response to a command if the portable wireless transponder device is within communications range of the antenna sending the command, the individual being locatable by determining with which antenna the interrogator was able to establish communications with the portable wireless transponder device.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This is a continuation of U.S. patent application Ser. No. 11/271,935, filed Nov. 10, 2005, titled “System and Method for Locating Individuals and Equipment, Airline Reservation System, Communication System”, which is a continuation of U.S. patent application Ser. No. 10/326,762, filed Dec. 20, 2002, now U.S. Pat. No. 7,030,732, issued Apr. 18, 2006, which in turn is a continuation of U.S. patent application Ser. No. 09/628,876, filed Jul. 26, 2000, now U.S. Pat. No. 6,509,829, issued Jan. 21, 2003, which in turn is a continuation of U.S. patent application Ser. No. 09/305,182, filed May 3, 1999, now U.S. Pat. No. 6,127,917, issued Oct. 3, 2000, which in turn is a continuation of U.S. patent application Ser. No. 08/807,678, filed Feb. 27, 1997, now U.S. Pat. No. 5,914,671, issued Jun. 22, 1999, all of which are incorporated herein by reference.
  • TECHNICAL FIELD
  • The invention relates to personnel locating systems, travel reservation systems, airport security systems, radio frequency identification devices.
  • BACKGROUND OF THE INVENTION
  • Travel reservation and baggage tracking systems are known in the art. Passengers typically purchase tickets in advance of travel, and are included in a database of a reservation system as having a reservation. On the date of travel, they must check in, or their seat will be given up to other passengers. Because statistics show that there will always be a number of passengers who will not show up on the designated date of travel, carriers typically “overbook” by selling a number of seats over the number of seats that are actually available, based on mathematical calculations. If the passenger does not check in, their seat may be used to accommodate overbooking, or may be given to standby passengers. The following U.S. patents relate to reservation systems and are incorporated herein by reference: U.S. Pat. Nos. 5,401,944; 5,151,692; 5,051,565; 5,010,240; 4,984,156; 4,931,932; 4,449,186; 4,247,795; 3,750,103.
  • When a passenger enters a travel depot (e.g., an airport), they must therefore check in to make sure the carrier (e.g., airline) knows they are present and to make sure that their seat is not given away to someone else. This typically involves standing in line and waiting for an employee to verify that the correct traveler is bearing a ticket. The employee receives the ticket and, using a reservation system, issues a boarding pass, with a seat assignment, indicating to the system that the seat is no longer available to be given away.
  • Traditionally, check in occurred simultaneously with a baggage check-in, with an employee marking the traveler's luggage with a tag indicting the destination where the bag is to be sent, printing a baggage receipt for the customer, and logging the bag in the reservation and baggage handling system.
  • Business travelers, however, typically do not have any bags to check and prefer not to wait in line. Also, many airports offer curbside check-in, which allows a passenger to check in bags at the curb before entering the airport, where lines are shorter because a gratuity is expected. The business travelers and travelers who have used the curbside check in typically go directly to the podium adjacent the departure gate and check in there. While the line at the podium may be shorter, it is still a line. Travelers needing to check in baggage must wait in lines.
  • There are many reasons why it would be useful to determine the presence of an individual in an airport or other travel depot. If a flight is about to leave, airline staff may desire to make an attempt to determine if a checked in passenger is in the airport. It is also frequently desirable to locate airline staff, such as pilots, flight attendants, wheelchair attendants, mechanics etc., or airport staff, such as security, or merchants or other persons who work in airports, for a variety of reasons. This is presently attempted through paging, which is sometimes difficult to hear, and is often annoying or competing with more important messages, such as gate change announcements, or information about which rows are boarding.
  • It is also useful to determine the location of a passenger in evaluating terrorist threats. A terrorist who has planted a bomb in his or her luggage is likely to leave the premises and not board the flight for which the luggage was checked.
  • Passengers in airports typically need gate and flight information in a hurry. Such information may be obtained from airline staff, but this typically involves standing in long lines. This information is therefore more typically gathered by reading a monitor which lists flight numbers, destinations, gates, and status. A problem is that in some airports, each airline has their own monitors, so a traveler may have to walk a great distance to try to find a monitor for a particular airline. Monitors also contain vast amounts of information, most of it of no interest to a particular traveler. This makes it difficult to find useful information in a hurry.
  • Switching antennas connected to an interrogator is disclosed in commonly assigned U.S. patent application Ser. No. 08/772,173, filed Dec. 18, 1996, titled “Communication System Including Diversity Antenna Queuing,” and listing Clifton W. Wood, Jr. as inventor, now U.S. Pat. No. 5,842,118. Antenna switching for this application is performed for diversity purposes.
  • SUMMARY OF THE INVENTION
  • The invention provides a system for locating an individual in a facility. The system comprises a portable wireless transponder device borne by the individual; an interrogator; and a plurality of antennas distributed in the facility. The antennas are selectively separately connected to the interrogator. The interrogator, when connected to any of the antennas has a communications range covering less than the area of the entire facility. The interrogator repeatedly transmits a wireless command to the portable wireless transponder device using alternating antennas. The portable wireless transponder device transmits data identifying the portable wireless transponder device in response to a command if the portable wireless transponder device is within communications range of the antenna sending the command. Thus, the individual is located by determining with which antenna the interrogator was able to establish communications with the portable wireless transponder device.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • Preferred embodiments of the invention are described below with reference to the following accompanying drawings.
  • FIG. 1 is a plan view of a travel depot facility, such as an airport, including a system, embodying the invention, for locating an individual.
  • FIG. 2 is a block diagram of the system of FIG. 1, further including an interface with an airline reservation and baggage tracking system, and further including monitors for displaying information of particular interest to passengers in the area of the monitor.
  • FIG. 3 is a perspective view showing a monitor included in the system of FIG. 2.
  • FIG. 4 is a front view of a card used in the system of FIG. 1 or 2.
  • FIG. 5 is a circuit schematic of an interrogator included in the system of FIG. 1 or 2.
  • FIG. 6 is a circuit schematic of circuitry included in card of FIG. 4.
  • FIG. 7 is a block diagram of an interrogator included in the system of FIG. 1 or 2.
  • FIG. 8 is a circuit schematic of DPSK circuitry included in the interrogator of FIG. 7.
  • FIG. 9 is a circuit schematic of RF circuitry included in the interrogator of FIG. 7.
  • FIG. 10 is a plan view of a card in accordance with an alternative embodiment of the invention.
  • FIG. 11 is a block diagram illustrating assembly of the card of FIG. 10.
  • FIG. 12 is a flow chart illustrating a routine run by the system of FIG. 1 or 2 to log locations of individuals.
  • FIG. 13 is a flow chart illustrating a routine run by the system of FIG. 1 or 2, used in connection with the routine of FIG. 12, to determine the location of an individual.
  • FIG. 14 is a flow chart illustrating a routine run by the system of FIG. 2 to check in a passenger using the card of FIG. 4 or 10 as an electronic boarding pass.
  • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).
  • FIG. 1 shows a travel depot facility 10, such as an airport, including a system 12 (see FIG. 2) for locating an individual. The facility 10 includes various areas of a typical facility such as a main terminal area 14 which typically includes a baggage check in area 16, shops, restaurants, etc. The facility 10 further includes a terminal concourse area 18 which one enters after passing a security check point 20. The terminal concourse area 18 includes multiple gate doors 22 defining controlled access points. More particularly, the gate doors 22 are typically locked until a flight is available for departure or is being deplaned. Airline staff control passage through the gate doors and only permit people with boarding passes through the gate doors 22. The gate doors 22 lead to jetways 24 which are movable to define a path into an airplane. The terminal area 18 typically includes podiums 28 where airline personnel are located. The terminal area 18 also includes multiple seating areas 30 which may be grouped off by gate.
  • The system 12 (see FIG. 2) includes portable wireless transponder devices 32 borne by passengers, airport employees, contractors, airline and contractor employees, etc. In the illustrated embodiment, the devices 32 include circuitry such as the circuitry described in detail in commonly assigned U.S. patent application Ser. No. 08/705,043, filed Aug. 29, 1996, now U.S. Pat. No. 6,130,602, and incorporated herein by reference. In one embodiment, the portable transponder devices 32 have card shaped housings with length and width dimensions corresponding to standard length and width dimensions of credit cards. In one embodiment, the transponder devices 32 include photographs of the respective individuals associated with the devices. The transponder devices 32 are, more particularly, intelligent radio frequency identification devices or remote intelligent communications (RIC) devices which communicate at microwave frequencies.
  • FIG. 4 shows but one example of a housing for a device 32, in the form of an employee identification badge or card including an intelligent radio frequency identification device integrated circuit 34. The integrated circuit 34 includes a transmitter, a receiver, a microprocessor, and a memory. The housing for the device 32 shown in FIG. 4 includes a card 36 made of plastic or other suitable material. In one embodiment, the integrated circuit 34 is laminated to the back face of the card 36, and the card forms a visible portion of the badge. In another embodiment, the integrated circuit 34 is bonded to the back face of the card by embedding it within a thin bond line of epoxy-based material. Alternatively, the integrated circuit 34 is embedded into the plastic card 36. In one embodiment, the front face of the badge has visual identification features including a photograph 38 of the bearer as well as identifying text. The device 32 further includes a send/receive antenna 40 coupled to the integrated circuit 34, and a battery 42 coupled to the integrated circuit 34 to supply power to the integrated circuit. The battery 42 and antenna 40 are embedded or supported inside the plastic card 36.
  • The battery 42 can take any suitable form. Preferably, the battery type will be selected depending on weight, size, and life requirements for a particular application. In one embodiment, the battery 42 is a thin profile button-type cell forming a small, thin energy cell more commonly utilized in watches and small electronic devices requiring a thin profile. A button-type cell has a pair of electrodes, an anode formed by one face and a cathode formed by an opposite face. Exemplary button-type cells are disclosed in several pending U.S. patent applications including U.S. patent application Ser. No. 08/205,957, “Button-Type Battery Having Bendable Construction and Angled Button-Type Battery,” listing Mark E. Tuttle and Peter M. Blonsky as inventors, now U.S. Pat. No. 5,432,027; U.S. patent application Ser. No. 08/321,251, “Button-Type Batteries and Method of Forming Button-Type Batteries,” listing Mark E. Tuttle as inventor, now U.S. Pat. No. 5,494,495; and U.S. patent application Ser. No. 08/348,543, “Method of Forming Button-Type Batteries and a Button-Type Battery Insulating and Sealing Gasket,” listing Mark E. Tuttle as inventor. These patent applications and resulting patents are hereby incorporated by reference. In an alternative embodiment, the battery 42 comprises a series connected pair of button type cells. Alternative power supplies can be used instead of batteries, in alternative embodiments.
  • FIG. 5 illustrates but one alternative housing supporting the circuit 34. More particularly, FIG. 5 illustrates a miniature housing 42 encasing the circuit 34 to define a tag which can be supported by a person or object. The housing 42 preferably has the general shape and size, in plan view, of a postage stamp. The embodiment of FIG. 5 also houses a card 44 supporting the circuit 34 in the housing 42. The card 44 is formed of plastic or other suitable material having a thickness of about 0.040 inches, a width of about 1.25 inches, and a height of about 1.25 inches. In one embodiment, the circuit 34 is bonded to a back face of the card 44 with a thin layer of non-conductive epoxy material that cooperates with the card to define the housing 42. The circuit 34 is coupled to a send antenna 48, and a receive antenna 46, and receives power from a battery 42 which can be similar to the battery included in the embodiment of FIG. 4. The battery 42, and antennas 46 and 48 are supported in the housing 42 by the card 44.
  • Although two particular types of housings have been disclosed, the circuit 34 can be included in any appropriate housing. The circuit 34 is of a small size that lends itself to applications employing small housings, such as cards, miniature tags, etc. Larger housings can also be employed. The circuit 34, housed in any appropriate housing, can be supported from a person, or attached to a object (or a peoples possessions) in any desired manner; for example using double sided tape, glue, lanyards, leash, nails, staples, rivets, or any other fastener. The housing can be sewn on to an object, hung from an object, implanted in an object (hidden), etc.
  • Various configurations are possible for the antenna connected to the circuit 34. In one embodiment, separate antennas 46 and 48 are provided for receiving and sending (FIG. 5). In another embodiment, a single antenna 40 is shared by the receiver and transmitter (FIG. 4). In one embodiment, one or more antennas are defined by conductive epoxy screened onto a card or housing. In the illustrated embodiment, the antenna is conductively bonded to the integrated circuit 34 via bonding pads.
  • The system 12 further includes an interrogator 50. The card 36 transmits and receives radio frequency communications to and from the interrogator 50. The system 12 further includes an array of antennas 52 (or send/receive antenna pairs) alternately coupled to the interrogator 50. The interrogator 50 includes transmitting and receiving circuitry, similar to that implemented in the circuit 34. In one embodiment, the system 12 further includes a controller 54. In the illustrated embodiment, the controller 54 is a computer. The controller 54 acts as a master in a master-slave relationship with the interrogator 50. The controller 54 includes an applications program for controlling the interrogator 50 and interpreting responses, and a library of radio frequency identification device applications or functions. Most of the functions communicate with the interrogator 50. These functions effect radio frequency communication between the interrogator 50 and the card 32. In one embodiment, the controller 54 and the interrogator 50 are combined together (e.g., in a common housing), or functions of the host computer are implemented in hard wired digital logic circuitry.
  • In the illustrated embodiment, the communications system 10 includes multiple selectable transmit antennas X1, X2, X3 etc., and multiple receive antennas R1, R2, R3 etc. connected to the interrogator 50. Each antenna pair X1, R1, X2, R2, etc. defines an antenna 52 of the antenna array for purposes of the discussion below. In one embodiment, the communications system 10 includes combined antennas that are used both for transmitting and receiving by the interrogator 50. Generally, the interrogator 50 transmits an interrogation signal or command, such as an “Identify” command, (“forward link”) via one of the antennas 52. The card 32 receives the incoming interrogation signal via its antenna, if it is within receiving range of the particular antenna 52 used to transmit. Upon receiving the signal, the card 32 responds by generating and transmitting a responsive signal or reply (“return link”). The interrogator 50 is described in greater detail below.
  • In the illustrated embodiment, the responsive signal is encoded with information that uniquely identifies, or labels the particular card 32 that is transmitting, so as to identify any object or person with which the card 32 is associated.
  • In the embodiment illustrated in FIG. 2, multiple cards 32 are employed; however, there is no communication between the cards 32. Instead, the multiple cards 32 communicate with the interrogator 50. Multiple cards 32 can be used in the same range of an antenna 52.
  • Various U.S. patent applications, which are incorporated herein by reference, disclose features that are employed in various alternative embodiments of the invention: Ser. No. 08/092,147, filed Jul. 15, 1993, “Wake Up Device for a Communications System” and continuation application Ser. No. 08/424,827, filed Apr. 19, 1995, “Wake Up Device for a Communications System”; Ser. No. 08/281,384, filed Jul. 27, 1994, “Communication System Having Transmitter Frequency Control”; Ser. No. 07/990,918, filed Dec. 15, 1992, now U.S. Pat. No. 5,365,551, “Data Communication Transceiver Using Identification Protocol”; Ser. No. 07/899,777, filed Jun. 17, 1992, “Radio Frequency Identification Device (RFID) and Method of Manufacture, Including an Electrical Operating System and Method,” now abandoned; Ser. No. 07/151,599, filed Nov. 12, 1993, now U.S. Pat. No. 5,406,263, “Anti-Theft Method for Detecting The Unauthorized Opening of Containers and Baggage,”; Ser. No. 07/168,909, filed Dec. 17, 1993, now U.S. Pat. No. 5,497,140, “Electrically Powered Postage Stamp or Mailing or Shipping Label Operative with Radio Frequency (RF) Communication,”; and Ser. No. 08/032,384, filed on Mar. 17, 1993, “Modulated Spread Spectrum in RF Identification Systems Method,” now allowed.
  • The integrated circuit 34 is advantageous over prior art devices that utilize magnetic field effect systems because, with the circuit 34, a greater range can be achieved, and more information can be obtained (instead of just an identification number). As a result, the circuit 34 can be used for the application of the present invention, where transmission over a large range is required. In one embodiment, the sensitivity of the cards 32 is adjustable so that only devices within an adjustable range of an antenna 52 will respond. In another embodiment, the power of the interrogator 50 is adjustable so that only devices within a certain range of an antenna 52 will respond.
  • A power conservation problem is posed by such implementations where batteries are used to supply power to the integrated circuits 34. If the integrated circuit 34 operates continuously at full power, battery life will be short, and card 32 will have to be frequently replaced. If the battery 42 is permanently sealed in a housing, replacement of the battery will be difficult or impossible. For example, one reason for sealing the battery with the integrated circuit 34 and antenna(s) in a housing is to simplify the design and construction, to reduce the cost of production, and protect the electrical interconnections between devices. Another reason is protection of the battery and integrated circuit 34 from moisture and contaminants. A third reason is to enhance the cosmetic appeal of the card 32 by eliminating the need for an access port or door otherwise necessary to insert and remove the battery. When the battery is discharged, the entire badge or stamp is then discarded. It is therefore desirable to incorporate power conservation techniques into the integrated circuit 32 in order to extend useful life.
  • FIG. 6 is a circuit schematic of the integrated circuit 34 utilized in the devices of FIG. 4 or 5. In the embodiment shown in FIG. 6, the circuit 34 is a monolithic integrated circuit. In the illustrated embodiment, the integrated circuit 34 comprises a single die, having a size of 209×116 mils2. The integrated circuit 34 includes a receiver 56, a transmitter 58, a micro controller or microprocessor 60, a wake up timer and logic circuit 62, a clock recovery and data recovery circuit 64, and a bias voltage and current generator 66.
  • In one embodiment, the circuit 34 switches between a “sleep” mode of operation, and higher power modes to conserve energy and extend battery life during periods of time where no interrogation signal is received by the circuit 34. The wake up timer and logic circuitry 62 provides this switching.
  • In one embodiment, a spread spectrum processing circuit 68 is also included in the circuit 34. In this embodiment, signals transmitted and received by the interrogator 50, and signals transmitted and received by the circuit 34 are modulated spread spectrum signals. Spread spectrum modulation is described below. In one illustrated embodiment, the modulation scheme for replies sent by the transmitter 58 is selectable. One of the available selections for replies sent by the transmitter 58 is modulated spread spectrum.
  • Spread Spectrum Modulation
  • Many modulation techniques minimize required transmission bandwidth. However, the spread spectrum modulation technique employed in the illustrated embodiment requires a transmission bandwidth that is up to several orders of magnitude greater than the minimum required signal bandwidth. Although spread spectrum modulation techniques are bandwidth inefficient in single user applications, they are advantageous where there are multiple users, as is the case with the instant circuit 34. The spread spectrum modulation technique of the illustrated embodiment is advantageous because the interrogator signal can be distinguished from other signals (e.g., radar, microwave ovens, etc.) operating at the same frequency. The spread spectrum signals transmitted by the circuit 34 and by the interrogator 50 are pseudo random and have noise-like properties when compared with the digital command or reply. The spreading waveform is controlled by a pseudo-noise or pseudo random number (PN) sequence or code. The PN code is a binary sequence that appears random but can be reproduced in a predetermined manner by the circuit 34. More particularly, incoming spread spectrum signals are demodulated by the circuit 34 or by the interrogator 50 through cross correlation with a version of the pseudo random carrier that is generated by the circuit 34 itself or the interrogator 50 itself, respectfully. Cross correlation with the correct PN sequence unspreads the spread spectrum signal and restores the modulated message in the same narrow band as the original data.
  • A pseudo-noise or pseudo random sequence (PN sequence) is a binary sequence with an autocorrelation that resembles, over a period, the autocorrelation of a random binary sequence. The autocorrelation of a pseudo-noise sequence also roughly resembles the autocorrelation of band-limited white noise. A pseudo-noise sequence has many characteristics that are similar to those of random binary sequences. For example, a pseudo-noise sequence has a nearly equal number of zeros and ones, very low correlation between shifted versions of the sequence, and very low cross correlation between any two sequences. A pseudo-noise sequence is usually generated using sequential logic circuits. For example, a pseudo-noise sequence can be generated using a feedback shift register.
  • A feedback shift register comprises consecutive stages of two state memory devices, and feedback logic. Binary sequences are shifted through the shift registers in response to clock pulses, and the output of the various stages are logically combined and fed back as the input to the first stage. The initial contents of the memory stages and the feedback logic circuit determine the successive contents of the memory.
  • The illustrated embodiment employs direct sequence spread spectrum modulation. A direct sequence spread spectrum (DSSS) system spreads the baseband data by directly multiplying the baseband data pulses with a pseudo-noise sequence that is produced by a pseudo-noise generator. A single pulse or symbol of the PN waveform is called a “chip.” Synchronized data symbols, which may be information bits or binary channel code symbols, are added in modulo-2 fashion to the chips before being modulated. The receiver performs demodulation. For example, in one embodiment the data is phase modulated, and the receiver performs coherent or differentially coherent phase-shift keying (PSK) demodulation. In another embodiment, the data is amplitude modulated. Assuming that code synchronization has been achieved at the receiver, the received signal passes through a wideband filter and is multiplied by a local replica of the PN code sequence. This multiplication yields the unspread signal.
  • A pseudo-noise sequence is usually an odd number of chips long. In the illustrated embodiment, one bit of data is represented by a thirty-one chip sequence. A zero bit of data is represented by inverting the pseudo-noise sequence.
  • Spread spectrum techniques are also disclosed in the following patent applications and patent, which are incorporated herein by reference: U.S. patent application Ser. No. 08/092,147; U.S. patent application Ser. No. 08/424,827, filed Apr. 19, 1995, now U.S. Pat. No. 5,790,946; and U.S. Pat. No. 5,121,407 to Partyka et al. They are also disclosed, for example, in “Spread Spectrum Systems,” by R. C. Dixon, published by John Wiley and Sons, Inc.
  • Backscatter and Frequency Hopping
  • The interrogator 50 sends out a command that is spread around a certain center frequency (e.g., 2.44 GHz). After the interrogator transmits the command, and is expecting a response, the interrogator switches to a CW mode (continuous wave mode). In the continuous wave mode, the interrogator does not transmit any information. Instead, the interrogator just transmits 2.44 GHz radiation. In other words, the signal transmitted by the interrogator is not modulated. After the circuit 34 receives the command from the interrogator, the circuit 34 processes the command. If the circuit 34 is in a backscatter mode it alternately reflects or does not reflect the signal from the interrogator to send its reply. For example, in the illustrated embodiment, two halves of a dipole antenna are either shorted together or isolated from each other to send a reply.
  • Frequency hopping is employed in one embodiment. In the illustrated embodiment, frequency hopping does not occur when the interrogator transmits a command, but occurs when the interrogator is in the continuous wave mode. The interrogator, in the continuous wave mode, hops between various frequencies close to the 2.44 GHz frequency. These various frequencies are sufficiently close to the 2.44 GHz frequency that backscatter antenna reflection characteristics of the circuit 34 are not appreciably altered. Because the interrogator is hopping between frequencies, the interrogator knows what frequency backscatter reflections to expect back from the circuit 34. By hopping between various frequencies, the amount of time the interrogator continuously uses a single frequency is reduced. This is advantageous in view of FCC regulatory requirements.
  • In one illustrated embodiment, no attempt is made to frequency hop at the interrogator to a pseudo-random sequence and then correlate to that at the receiver. However, in alternative embodiments, such correlation takes place.
  • In one embodiment, the transmitter 58 is switchable between operating in a modulated backscatter transmitter mode, and operating in an active mode. The transmitter 58 switches between the backscatter mode and the active mode in response to a radio frequency command, instructing the transmitter to switch, sent by the interrogator 50 and received by the receiver 56. In the active mode, a carrier for the transmitter 58 is extracted from a signal received by the receiver 56.
  • Active transmitters are known in the art. See, for example, U.S. patent application Ser. No. 08/281,384; U.S. patent application Ser. No. 08/281,384 also discloses how transmit frequency for the transmitter 58 is recovered from a message received via radio frequency from the interrogator 50.
  • In one embodiment, the transmitter 58 is capable of transmitting using different modulation schemes, and the modulation scheme is selectable by the interrogator. More particularly, if it is desired to change the modulation scheme, the interrogator sends an appropriate command via radio frequency. In this embodiment, the transmitter can switch between multiple available modulation schemes such as Binary Phase Shift Keying (BPSK), Direct Sequence Spread Spectrum, On-Off Keying (OOK), and Modulated Backscatter (MBS).
  • In one embodiment, the clock for the entire integrated circuit 16 is extracted from the incoming message itself by clock recovery and data recovery circuitry 64. This clock is recovered from the incoming message, and used for timing for the micro controller 60 and all the other clock circuitry on the chip, and also for deriving the transmitter carrier or the subcarrier, depending on whether the transmitter is operating in active mode or backscatter mode.
  • In addition to recovering a clock, the clock recovery and data recovery circuit 64 also performs data recovery on valid incoming signals. The valid spread spectrum incoming signal is passed through the spread spectrum processing circuit 68, and the spread spectrum processing circuit 68 extracts the actual ones and zeros of data from the incoming signal. More particularly, the spread spectrum processing circuit 68 takes the chips from the spread spectrum signal, and reduces each thirty-one chip section down to a bit of one or zero, which is passed to the micro controller 60.
  • The micro controller 60 includes a serial processor, or I/O facility that received the bits from the spread spectrum processing circuit 68. The micro controller 60 performs further error correction. More particularly, a modified hamming code is employed, where each eight bits of data is accompanied by five check bits used by the micro controller 60 for error correction. The micro controller 60 further includes a memory, and after performing the data correction, the micro controller 60 stores bytes of the data bits in memory. These bytes contain a command sent by the interrogator 50. The micro controller 60 responds to the command.
  • For example, the interrogator 50 may send a command over one of the antennas 52 requesting that any integrated circuit 34 in communications range of that antenna 52 respond with the integrated circuit's identification number. Status information is also returned to the interrogator 50 from the integrated circuit 34 when the circuit 34 responds.
  • The transmitted replies have a format similar to the format of incoming messages. More particularly, a reply starts with a preamble (e.g., all zeros in active mode, or alternating double zeros and double ones in backscatter mode), followed by a Barker or start code which is thirteen bits long, followed by actual data.
  • No stop bits are included in the incoming message or reply, in the preferred embodiment. Instead, part of the incoming message describes how many bytes are included, so the integrated circuit 34 knows how much information is included. Similarly, part of the outgoing reply describes how many bytes are included, so the interrogator 50 knows how much information is included. The incoming message and outgoing reply preferably also include a check sum or redundancy code so that the integrated circuit 34 or the interrogator 50 can confirm receipt of the entire message or reply.
  • After the reply is sent, the integrated circuit 34 returns to the sleep mode, and the wake up timer and logic circuit 62 starts timing again for the next wake up (e.g., in 16 milliseconds, or whatever period is selected).
  • The interrogator 50 provides a communication link between the controller 54 and the integrated circuit 34. In one embodiment, the interrogator 50 connects to the controller 54 via an IEEE-1284 enhanced parallel port (EPP). The interrogator communicates with the circuit 34 via a selected RF (microwave) antenna 52.
  • In one embodiment, communications from the interrogator 50 to the circuit 34, and communications from the circuit 34 to the interrogator 50 use different physical protocols.
  • The physical communications protocol for communications from the interrogator 50 to the circuit 34 is referred to as the “forward link” protocol. The forward link data is sent in the following order:
  • Preamble
  • Barker Code
  • Command Packet
  • Check Sum
  • A Maximal Length Pseudo Noise (PN) Sequence is used in the Direct Sequence Spread Spectrum (DSSS) communications scheme in the forward link. In one embodiment, the sequence is generated by a linear feedback shift register of the form [5,2]. That is, there are five registers, the output of the second register is X-ORed with the output of the fifth register, and the result is fed into the input of the first register one. This produces a repeating 31 “chip” sequence. The sequence ends with all registers set to one. The sequence is taken from the output of the first register. This code is synchronous with the data in that each data bit comprises one and only one full PN sequence. The chip sequence for each bit is:
  • 001 1010 0100 0010 1011 1011 0001 1111.
  • Other embodiments are, of course, possible. For example, other forms of linear feedback shift registers can be employed.
  • In one embodiment, a zero bit is transmitted as one inverted full cycle of the PN sequence. A one bit is transmitted as one full non-inverted cycle of the PN sequence.
  • In the illustrated embodiment, the data is not differentially encoded.
  • In one embodiment, there are at least two available “chipping” rates. One rate is 9.5375 Mchips/sec (high band) and another rate is 4.768750 Mchips/sec (low band).
  • The preamble precedes the data. In one embodiment, the preamble includes a series of zeros, followed by a start or Barker code. In embodiments where the transponder 16 includes wake up timer and logic circuitry 36, the preamble includes a series of zeros for a duration equal to the wakeup interval (e.g., 5, 16, 64, or 256 ms) plus 2 milliseconds, followed by a start or Barker code.
  • In one embodiment, the Barker code is defined by the following bit string:
  • 1111 1001 1010 1. Other embodiments are possible.
  • Command data is grouped into 13-bit words. Each word includes eight data bits (D7, D6, D5, D4, D3, D2, D1, D0) and five ECC (Error Correction Code) bits (P4, P3, P2, P1, and P0). In one embodiment, the bit transmission order is (with D7 transmitted first):
  • D7, D6, D5, D4, D3, D2, D1, D0, P4, P3, P2, P1, P0 . . .
  • In one embodiment, the ECC bits (P4-P0) are generated using the following equations:
    P0=(D1+D2+D5+D7)modulo 2
    P1=[(D1+D3+D4+D6)modulo 2]Complement
    P2=(D0+D2+D3+D6+D7)modulo 2
    P3=[(D0+D4+D5+D6+D7)modulo 2]Complement
    P4=(D0+D1+D2+D3+D4+D5)modulo 2.
  • Data rates depend on which data band is being used. A high data band has an effective data rate (adjusting for PN and ECC) of 189.3 Kbps. A low data band has an effective data rate of 94.68 Kbps.
  • In the illustrated embodiment, a 16-bit check sum is provided to detect bit errors on the packet level. A circuit 34 can be programmed to either return a reply if a bad check sum is found in the forward link, or to simply halt execution and send no replies. In one embodiment, a 16 bit CRC is employed in the forward link, the return link, or both, instead of or in addition to the check sum.
  • The physical communications protocol for communications from the circuit 34 to the interrogator 50 is referred to as the “return link” protocol. In the illustrated embodiment, the return link messages are sent in the following order:
  • Preamble
  • Barker Code
  • Reply Packet
  • Check Sum
  • After sending a command, the interrogator sends a continuous unmodulated RF signal with a frequency of 2.44175; Ghz. Return link data is Differential Phase Shift Key (DPSK) modulated onto a square wave subcarrier with a frequency of 596.1 Khz. A data 0 corresponds to one phase and data 1 corresponds to another, shifted 180 degrees from the first phase. The subcarrier is used to modulate antenna impedance of a card 32. For a simple dipole, a switch between the two halves of the dipole antenna is opened and closed. When the switch is closed, the antenna becomes the electrical equivalent of a single half-wavelength antenna that reflects a portion of the power being transmitted by the interrogator. When the switch is open, the antenna becomes the electrical equivalent of two quarter-wavelength antennas that reflect very little of the power transmitted by the interrogator. The switch driving a printed half wavelength dipole antenna gives a typical range of 15 feet when the interrogator 50 transmits at 30 dBm into a 6 dB gain antenna. Therefore, antennas 52 are located no more than 15 feet apart in areas of the facility 10 where it is desirable to locate people or objects.
  • The preamble for the return link includes 2000 bits, alternating 2 zeros then 2 ones, etc., and a 13-bit start (Barker) code. Alternative preambles are possible.
  • In the illustrated embodiment, the start code or Barker Code is defined by the following bit string: 1111 1001 1010 1.
  • The reply link data is grouped in 13 bit words. Each word is composed of 8 data bits (D7, D6, D5, D4, D3, D2, D1, D0) and 5 ECC bits (P4, P3, P2, P1, P0).
  • The Block Encoded Sequence is D7, D6, D5, D4, D3, D2, D1, D0, P4, P3, P2, P1, P0.
  • The Block ECC Bits (P4-P0) are generated using the following equations:
    P0=(D1+D2+D5+D7)modulo 2
    P1=[(D1+D3+D4+D6)modulo 2]Complement
    P2=(D0+D2+D3+D6+D7)modulo 2
    P3=[(D0+D4+D5+D6+D7)modulo 2]Complement
    P4=(D0+D1+D2+D3+D4+D5)modulo 2.
  • In the illustrated embodiment, the bit duration is 6.71 μs making the effective data rate 91.75 Kbps for the return link.
  • In the illustrated embodiment, a 16-bit check sum is provided to detect bit errors on the packet level. In one embodiment, a 16 bit CRC is employed in addition to or instead of the check sum.
  • Each pair of data words is interleaved, starting with the Barker code and the first data word. The transmitted bit order for two sequential words, A and B, is D7A, D7B, D6A, D6B, D5A, D5B, D4A, D4B, D3A, D3B, D2A, D2B, D1A, D1B, D0A, D0B, P4A, P4B, P3A, P3B, P2A, P2B, P1A, P1B, P0A, P0B.
  • D7A is the first transmitted bit. In the illustrated embodiment, DPSK is applied to the interleaved data.
  • In one embodiment (see FIG. 7), the interrogator 50 includes enhanced parallel port (EPP) circuitry 70, DPSK (differential phase shift keyed) circuitry 72, and RF (radio frequency) circuitry 74, as well as a power supply (not shown) and a housing or chassis (not shown). In the illustrated embodiment, the enhanced parallel port circuitry 70, the DPSK circuitry 72, and the RF circuitry 74 respectively define circuit card assemblies (CCAs). The interrogator uses an IEEE-1284 compatible port in EPP mode to communicate with the controller 54. The EPP circuitry 70 provides all the digital logic required to coordinate sending and receiving a message to and from a circuit 34. The EPP circuitry 70 buffers data to transmit from the controller 54, converts the data to serial data, and encodes it. The EPP circuitry 70 then waits for data from the circuit 34, converts it to parallel data, and transfers it to the controller 54. In one embodiment, messages include up to 64 bytes of data.
  • The EPP mode interface provides an asynchronous, interlocked, byte wide, bidirectional channel controlled by the controller 54. The EPP mode allows the controller 54 to transfer, at high speed, a data byte to/from the interrogator within a single host computer CPU I/O cycle (typically 0.5 microseconds per byte).
  • The DPSK circuitry 72 (see FIG. 8) receives signals I and Q from the RF circuitry 74 (described below), which signals contain the DPSK modulated sub-carrier. The DPSK circuitry 72 includes anti-aliasing filters 76 and 78 filtering the I and Q signals, respectively, and analog to digital (A/D) converters 80 and 82 respectively coupled to the filters 76 and 78 and respectively converting the filtered signals from analog to digital signals. The DPSK circuitry 72 further includes a combiner 84, coupled to the A/ D converters 80 and 82, combining the digital signals. The DPSK circuitry 72 further includes a FIR matched filter 86, coupled to the combiner 84, which filters the combined signals. The DPSK circuitry 72 further includes delay circuitry 88 and multiplier circuitry 90 coupled to the FIR matched filter 86 for delaying the signal and multiplying the signal with the delayed signal to remove the sub-carrier. The DPSK circuitry 72 further includes low pass filter circuitry 92, coupled to the multiplier 90, filtering the output of the multiplier 90 to remove the X2 component. The DPSK circuitry 72 further includes a bit synchronizer 94 coupled to the filter 92 for regeneration of the data clock. The DPSK circuitry 72 further includes lock detect circuitry 96 coupled to the low pass filter 92 and generating a lock detect signal. The data, clock, and lock detect signal are sent to the EPP circuitry 70.
  • The RF circuitry 74 (see FIG. 9) interfaces with the transmit and receive antennas X1, X2, X3, etc., and R1, R2, R3, etc defining antennas 52. The RF circuitry modulates the data for transmission to a circuit 34, provides a continuous wave (CW) carrier for backscatter communications with a circuit 34 (if backscatter communications are employed), and receives and downconverts the signal received from the transponder unit (which is a backscatter signal in one embodiment).
  • The RF circuitry 74 also includes a power divider 98, and a frequency synthesizer 100 coupled to the power divider 98. The frequency synthesizer 100 tunes the RF continuous waver carrier for frequency hopping and band selection. The RF circuitry defines a transmitter, and receives data from the EPP circuitry 70. The RF circuitry 74 includes an amplitude modulation (AM) switch 102 that receives the data from the EPP circuitry 70 and amplitude modulates the data onto a carrier. More particularly, the AM switch 102 turns the RF on and off (ON OFF KEY). The RF circuitry 74 further includes a power amplifier 104, coupled to the AM switch 102, to amplify the signal. The RF circuitry 74 further includes a switch 106, coupled to the power amplifier 104, for transmission of the amplified signal through a selected one of the transmit antennas X1, X2, X3, etc.
  • During continuous wave (CW) transmission for the backscatter mode, the AM switch 102 is left in a closed position. When the interrogator 50 is transmitting in the CW mode, the circuit 34 backscatters the signal with a DPSK modulated sub carrier. This signal is received via one of the receive antennas R1, R2, R3, etc. More particularly, the RF circuitry 74 further includes a switch 108 coupled to the receive antennas R1, R2, R3, etc. In another alternative embodiment, such as when backscatter communications are not employed, the RF circuitry uses common antennas for both transmission and reception, and alternates use of antennas from multiple available send/receive antennas. The RF circuitry 74 further includes a low noise amplifier (LNA) 110 coupled to the switch 108 and amplifying the received signal. The RF circuitry 74 further includes a quadrature downconverter 112, coupled to the LNA 110, coherently downconverting the received signal. The RF circuitry 74 further includes automatic gain controls (AGCs) 114 and 116 coupled to the quadrature down converter 112. The amplitude of the signals are set using the automatic gain controls 114 and 116 to provide the signals I and Q. The I and Q signals, which contain the DPSK modulated sub-carrier, are passed on to the DPSK circuitry 72 (FIG. 8) for demodulation.
  • Although one interrogator 50 has been described, it may be desirable to provide multiple interrogators depending on the size and layout of a facility, in which case the multiple interrogators will preferably share information.
  • The interrogator or interrogators 50 are respectively selectively connected to the antennas 52 of an array of antennas distributed in at least the passenger areas of the facility, such as in the main terminal 14, the baggage check in area 16, the terminal concourse area 18, and the security check area 20. An interrogator connected to any of the antennas 52 has a range covering less than the area of the entire facility 10. More particularly, the more antennas 52 that are provided, the more precisely the location of an individual can be determined (the transmission and reception range of the interrogator can be decreased appropriately). Preferably, some antennas 52 are located in non-passenger areas, such as outdoor areas, to assist in locating individuals or equipment instead of passengers. The antennas 52 are designed for transmission and reception at microwave frequencies (e.g., 2.44 GHz). As described above, the antennas 52 can either comprise combined send/receive antennas, or separate antennas for sending (transmitting) and receiving. If separate antennas are used for sending and receiving, they will be referred to as a single antenna for purposes of the following discussion and claims.
  • Preferably, the antennas 52 are distributed fairly evenly throughout monitored areas of the facility 10. In one embodiment, an area of communication is defined by the interrogator 50 connected to an antenna 52, and the area of communication of the interrogator using one of the antennas 52 overlaps with the area of communication of the interrogator using another one of the antennas 52 so that there are no gaps in the areas of the facility desired to be covered by the system.
  • In operation, the interrogator 52 repeatedly transmits a wireless command to the portable wireless transponder device using alternating ones of the antennas 52. In one embodiment, the interrogator is sequentially connected to respective antennas 52, and makes at least one communication attempt using each antenna 52. The device 32 owned by an individual or supported by an object or checked or carry-on luggage transmits data identifying the device 32 (and thus the bearer or possessor of the device 32) in response to an interrogator command if the device 32 is within communications range of the antenna 52 sending the command. Thus, the individual or object is located by determining with which antenna the interrogator 50 was able to establish communications with the portable wireless transponder device.
  • FIGS. 12 and 13 illustrate routines executed by the controller 54 to locate individuals, equipment, or checked or carry-on baggage in the facility 10. Note that it may be useful for an airline to determine the location of checked baggage, using the system of the invention, for various reasons. For example, it may be useful to locate a piece of baggage that has been misplaced, or that is destined for a flight that is about to leave, or a piece of baggage that is in transit to a plane, but must be re-routed to a different plane. It may be useful to locate a piece of carry on baggage using the system of the invention for various reasons. For example, if a piece of carry on baggage becomes separated from its owner for a predetermined time, an assumption can be made that it is either lost or else creates a possible bomb risk that should be investigated. Also, the system can be used to locate a passenger's lost carry on or checked baggage.
  • The routine of FIG. 12 is continuously run (during hours of operation of the facility) and includes a step 118 of causing the interrogator to send an “identify” command, which requests that all devices 32 (within communication range) reply with their respective identification numbers. After performing step 118, the controller 54 proceeds to step 120.
  • In step 120, the controller 54 deletes old entries and logs identification numbers of devices 32 within the range of the antenna 52 being used. After performing step 120, the controller 54 proceeds to step 122.
  • In step 122, the controller switches the antenna 52 (or antenna pair) being used by the interrogator. After performing step 122, the controller 54 proceeds to step 118.
  • The routine of FIG. 13 is run when it is desired to locate a specific individual, item of equipment, piece of carry-on baggage, or piece of checked baggage (by inputting an identification number of a device 32).
  • The routine of FIG. 13 includes a step 124 of receiving (inputting) an inquiry as to the location of a particular individual. After performing step 124, the controller 54 proceeds to step 126.
  • In step 126, the controller determines if the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) is on the carrier (plane) by checking the logs for antennas at controlled access points (e.g., the gate for the flight the individual was scheduled to take). After performing step 126, the system proceeds to step 128.
  • In step 128, a determination is made as to whether the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) is on the carrier. If so, the controller proceeds to step 130. If not, the controller proceeds to step 132.
  • In step 130, the location of the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) is displayed as being on board the carrier (e.g. the airplane). After performing step 130, execution terminates.
  • In steps 132 and 134 (which can be combined), current (most recent) logs are read for all other antennas, and the controller searches for the particular individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) in these logs. After performing steps 132 and 134, the controller proceeds to step 136.
  • In step 136, a determination is made as to whether the particular individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) was located in any of these logs. If so, the controller proceeds to step 140. If not, the controller proceeds to step 138.
  • In step 138, the controller causes a display to be generated that the search failed or the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) was not located on the premises. After performing step 138, execution terminates.
  • In step 140, a determination is made as to whether the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) was located in more than one log in logs associated with more than one antenna). If so, the controller proceeds to step 142. If not, the controller proceeds to step 144.
  • In step 142, the location is displayed of the antenna where the logged communication with the device of the particular individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) took place. This is presumably where the individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) is presently located. After performing step 142, execution terminates.
  • In step 144, because the individual has been logged in more than one antenna location, all antenna locations can be displayed or, in the illustrated embodiment, triangulation or telemetry are used, and/or relative signal strengths measured by the multiple antennas for the last logged reply by the card are used, to locate with particularity the particular individual's location (or the location of the item of equipment, or piece of carry-on baggage, or piece of checked baggage). Optionally, the direction of travel is also determined by determining change in triangulated location with respect to time. After performing step 144, the controller proceeds to step 146.
  • In step 146 the controller causes the location of the particular individual (or item of equipment, or piece of carry-on baggage, or piece of checked baggage) to be displayed. After performing step 146, the controller proceeds to step 148.
  • This system and routine can be used to track the location of equipment bearing the circuit 34, carry-on baggage bearing the equipment, or checked baggage bearing the equipment.
  • In one embodiment of the invention, the system 12 further comprises a carrier (e.g., airline) reservation and baggage tracking system 152 (FIG. 2). Any presently used reservation system can be employed. For example, a system such as the systems described in incorporated U.S. Pat. Nos. 5,401,944; 5,151,692; 5,051,565; 5,010,240; 4,984,156; 4,931,932; 4,449,186; 4,247,795; and 3,750,103 can be employed for the carrier reservation and baggage tracking system 152. The reservation and baggage tracking system 152 includes a computer having a database storing information identifying passengers who have purchased tickets for passage (e.g., a flight), information about scheduled departures (e.g., for flights), information identifying passengers who have checked in (e.g., for a flight), etc. The system 12 further includes a network 154 connecting the interrogator 50 to the carrier reservation and baggage tracking system 152. Any appropriate network, such as a local area network, wide area network, Intranet network, Internet network, etc. can be employed. If multiple airlines or carriers in the facility have separate reservation systems, the network 154 preferably connects all participating reservation systems to the interrogator 50.
  • In this embodiment, the card 32 is used to automatically check in a passenger who enters the facility or a designated area of the facility (e.g., a gate area), as desired.
  • More particularly, the interrogator 50 defines a wireless transponder in communication with the computer of the carrier reservation and baggage tracking system 152. The interrogator periodically sends wireless commands requesting responses from portable identification devices (e.g., the cards 32). The cards 32 transmitting identifying data (e.g., a serial number that is associated with the bearer, a Social Security Number, a frequent flyer number, a confirmation number, etc.) in response to receiving a command from the interrogator. The interrogator has a desired coverage area (e.g., in the airport, or in the gate area), and communicates only with cards 32 within the desired area. The computer of the carrier reservation and baggage tracking system 152 modifies the reservation database to indicate that a passenger has checked in, in response to the interrogator 50 receiving a response from a card 32 in the desired coverage area. Thus, the card 32 acts as an electronic boarding pass, saving the passenger from having to stand in line to check in, and reducing labor required by the carrier.
  • Conditions can be imposed before the electronic boarding pass is accepted. For example, in one embodiment, the electronic boarding pass (card 32) is accepted to check in a passenger only within a predetermined time period before a scheduled departure. Thus, if a passenger is in the airport the day before a flight (e.g., to greet an arriving passenger, or for an unrelated flight), the passenger is not considered to be checked in. In one embodiment, the electronic boarding pass is only accepted if the response from the card 32 includes identifying data for a passenger for whom the database in the carrier reservation and baggage tracking system 152 indicates that a ticket for a flight has been purchased. A routine for execution by the system 152 to this effect is provided in FIG. 14, and includes a first step 156 in which the system 152 retrieves a list of passengers having reservations for flights scheduled to leave in the next predetermined time period (e.g., flights scheduled to leave in the next two hours, or next one hour). After performing step 156, the system proceeds to step 158.
  • In step 158, a determination is made as to whether identification data (e.g., Social Security Number, frequent flier number, serial number, etc.) logged using designated antennas 52 (e.g., in the airport, or in the gate area for the particular flight, etc.) match the identification data of any passengers on the reservation list for flights scheduled to leave in the next predetermined time period. If so, the system proceeds to step 160. If not, the system proceeds to step 162.
  • In step 160, the system checks in the qualifying passengers (those logged using designated antennas and matching the identification data of passengers on the reservation list for flights scheduled to leave in the next predetermined time period). The system further assigns seats (this may be based on known customer preferences, such as preferences stored for frequent fliers), and moves the checked in passengers from the reservation list to the checked in list. This is so that there is no need to search for passengers who have already checked in, next time step 156 is executed. After performing step 160, the system proceeds to step 166.
  • In step 162, a time delay is imposed so that the system is freed up to perform other tasks. After performing step 162, the system proceeds to step 164.
  • In step 164, the time is updated. In other words, the system time is retrieved for purposes of defining the predetermined time period of step 156. After performing step 164, the system proceeds to step 156.
  • In step 166, a time delay is imposed so that the system is freed up to perform other tasks. After performing step 166, the system proceeds to step 168.
  • In step 168, the time is updated. In other words, the system time is retrieved for purposes of defining the predetermined time period of step 156. After performing step 168, the system proceeds to step 156.
  • In one embodiment, the transponder device 32 is manufactured using techniques such as those described in a commonly assigned U.S. patent application (attorney docket MI40-048) titled “Tamper Resistant Smart Card and Method of Protecting Data In a Smart Card”, filed Feb. 13, 1997, listing as inventor John R. Tuttle et al., now U.S. Pat. No. 5,988,510, and incorporated herein by reference. In one embodiment, the device 32 includes a magnetic stripe which the carrier (e.g., airline) can use for various purposes instead of or in addition to using the antennas 42. For example, an airline may use the antennas 42 to check in a passenger, but may use the magnetic stripe with a card reader at a gate 22 (such as the card reader described in U.S. Pat. No. 5,010,240) in place of a boarding card when a passenger passes through the gate 22 to board a plane, or vice versa.
  • In one embodiment, the system gives an indication to a passenger that the passenger has been successfully checked in, such as by displaying a message on a monitor, on a display on the card 32 (described elsewhere herein), by making an announcement on a speaker, or by other means.
  • In one embodiment, a similar method and routine is used to check in luggage bearing a card 32 (or a miniature tag housing the integrated circuit 34) which is configured to transmit data indicating the card is associated with checked baggage (instead of carry-on baggage or other equipment) in response to a command from the interrogator. The luggage can be checked in instead of or, preferably, in addition to the passenger. This way, the passenger can just leave the luggage in a designated area instead of waiting in a line. Airline personnel can determine the destination by interrogating the card 32 or tag on the baggage. Thus, the card 32 or tag becomes an electronic (recyclable) baggage tag. In one embodiment, the card 32 or tag on the checked baggage includes a display (as described elsewhere herein), which displays the destination of the baggage (and/or transfer points).
  • In one embodiment of the invention (see FIGS. 1-3), the system 12 communicates custom travel (e.g. flight) information to a passenger. The system 12 uses the computer of the previously described carrier reservation and baggage tracking system 152. The system further includes monitors 170 and/or speakers 172, and appropriate converters 174 and 176 connecting the monitors and speakers to the network. The converters 174, for example, may convert from EGA, VGA, or super VGA to a standard television signal, and the converters 176, for example, may be sound cards or equivalent circuitry. Whenever a passenger is in proximity to an antenna located near a monitor or speaker, the interrogator 50 determines this in the same way that the interrogator 50 locates passengers, by communicating with a card 32 possessed by the passenger. The system accesses the reservation and baggage tracking system 152, retrieves the departure information for that passenger, and displays the information on the monitor as shown in FIG. 3. More particularly, the system uses the existing reservation database of the system 152, including information identifying passengers who have purchased tickets for a flight, and information about scheduled departures. The information includes existing information such as a flight, bus or train number 178, destination 180, a gate, bay, or track number 182, scheduled departure time 184, and status information 186 (e.g., boarding, on time, delayed, gate change, see agent, cancelled, etc.).
  • If multiple passengers are in communications range of the antenna near the monitor 170, information will appear tailored for each of these passengers, as shown in FIG. 3. The information displayed therefore preferably includes the passenger's name 188 (or an identifying code or number known by the passenger), as well. The information may be sorted (arranged) by passenger name in alphabetical order, by scheduled departure time, or by order of detection of the passengers by the interrogator 50.
  • In one embodiment, shown in FIGS. 10 and 11, an alternative card 32B is provided which is similar to the card 32, but further includes a display 190 coupled to the integrated circuit 34. The display 190 can be a liquid crystal display, LED display, or other type of display. In this embodiment, the customized information for the passenger bearing the card 32B appears on the display 190. The display 190 can be activated by bringing the card 32B in communication range with a designated antenna 52 in the facility (which may be arranged to have a small range requiring close proximity, so the display is not continuously activated while the passenger travels through the facility). Alternatively, the card 32B is further include an actuator 192 coupled to the integrated circuit 34, actuation of which causes display of the information. The information can be similar to the information displayed on the monitor 170, if a monitor 170 is used, except that the name of the passenger may be omitted because the bearer of the card 32B is obviously the passenger. On the other hand, it may be desirable to display the passenger name to avoid mistaken swapping of the cards 32B or to avoid theft. The actuator 192 may be connected to an analog or digital input pin of the integrated circuit.
  • In the embodiment of FIGS. 10 and 11, the card further includes a buffer memory 194 coupled to a serial input/output port of the integrated circuit 34, a controller 196, and a display driver 198. The serial input output port is used to load the buffer memory 194, and then the controller 196 and display driver 198 drive the display 190.
  • Although the system of the invention has been described in connection with an airport and airline reservation system, it will be apparent that the system also has application to other travel depots and reservation systems, for those traveling by train, boat, bus, etc.
  • In one embodiment, systems of multiple facilities (airports) are connected together, such as by using a telephone link, wide area network, Internet, Intranet, etc., so that data can be shared among various systems. In this embodiment, the location of checked luggage, carry-on luggage, equipment, or individuals can be determined if the location is within communications range of an interrogator in any of the connected facilities (airports).
  • Various other applications for the system 10 will readily be apparent to those of ordinary skill in the art.
  • In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.

Claims (14)

1. A system for locating an object, the system comprising:
an output device;
a plurality of databases;
a plurality of interrogators, each interrogator electrically coupled to a plurality of antennas, each of the interrogators configured to communicate with radio frequency identification (RFID) tags within communication range of each respective interrogator; and
a plurality of controllers, each controller communicatively coupled to one or more of the interrogators and to one or more of the databases, each controller being further configured to store in one or more of the databases information associated with RFID tags within communication range of each respective interrogator, each of the controllers being further configured to receive an object identifier associated with the object and to access the databases to locate the object, each controller causing the output device to output a location of the object.
2. The system of claim 1, wherein the output device comprises a display.
3. The system of claim 2, wherein the display is incorporated on the RFID tags.
4. The system of claim 1, wherein the plurality of interrogators is communicatively coupled to each other and each interrogator is configured to share information with other interrogators.
5. The system of claim 1, wherein the plurality of databases comprises log files stored on each of the controllers.
6. The system of claim 1, wherein the object identifier comprises a unique number assigned to a person.
7. The system of claim 1, wherein the object comprises a person.
8. The system of claim 1, wherein the object comprises inventory.
9. A system for managing objects in a geographically dispersed environment, the system comprising:
a plurality of sites, each of the sites being remotely located from other sites;
a plurality of radio frequency identification (RFID) tags, each RFID tag being associated with an object;
one or more interrogators located at each site, each interrogator being communicatively coupled to one or more antennas and configured to communicate with and to log a presence of any RFID tag within communication range of the antennas;
a network communicatively coupling the one or more interrogators; and
an access system communicatively coupled to the network, the access system configured to receive identifying information associated with the object and to access a log to locate the object.
10. The system of claim 9, wherein the log comprises a database.
11. The system of claim 9, wherein the log comprises a log file stored on each respective interrogator.
12. The system of claim 9, wherein each of the one or more interrogators are communicatively coupled to the network via a controller.
13. The system of claim 9, wherein each interrogator is configured to share information with other interrogators.
14. The system of claim 9, wherein each interrogator is further configured to triangulate to determine a position of an RFID tag when the RFID tag is detected by a plurality of antennas.
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US08/807,678 US5914671A (en) 1997-02-27 1997-02-27 System and method for locating individuals and equipment, airline reservation system, communication system
US09/305,182 US6127917A (en) 1997-02-27 1999-05-03 System and method for locating individuals and equipment, airline reservation system, communication system
US09/628,876 US6509829B1 (en) 1997-02-27 2000-07-26 System and method for locating individuals and equipment, airline reservation system, communication system
US10/326,762 US7030732B2 (en) 1997-02-27 2002-12-20 System and method for locating individuals and equipment, airline reservation system, communication system
US11/271,935 US7570151B2 (en) 1997-02-27 2005-11-10 System and method for locating individuals and equipment, airline reservation system, communication system
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US09/628,876 Expired - Lifetime US6509829B1 (en) 1997-02-27 2000-07-26 System and method for locating individuals and equipment, airline reservation system, communication system
US10/326,762 Expired - Fee Related US7030732B2 (en) 1997-02-27 2002-12-20 System and method for locating individuals and equipment, airline reservation system, communication system
US11/271,935 Expired - Fee Related US7570151B2 (en) 1997-02-27 2005-11-10 System and method for locating individuals and equipment, airline reservation system, communication system
US11/845,701 Abandoned US20070290848A1 (en) 1997-02-27 2007-08-27 System and Method for Locating Individuals and Equipment, Airline Reservation System, Communication System
US11/845,706 Abandoned US20070290849A1 (en) 1997-02-27 2007-08-27 System and Method for Locating Individuals and Equipment, Airline Reservation System, Communication System
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US09/628,876 Expired - Lifetime US6509829B1 (en) 1997-02-27 2000-07-26 System and method for locating individuals and equipment, airline reservation system, communication system
US10/326,762 Expired - Fee Related US7030732B2 (en) 1997-02-27 2002-12-20 System and method for locating individuals and equipment, airline reservation system, communication system
US11/271,935 Expired - Fee Related US7570151B2 (en) 1997-02-27 2005-11-10 System and method for locating individuals and equipment, airline reservation system, communication system
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060061453A1 (en) * 1997-02-27 2006-03-23 Tuttle John R System and method for locating individuals and equipment, airline reservation system, communication system
US20090079565A1 (en) * 2007-09-26 2009-03-26 General Electric Company System and method for tracking an inventory within an asset
US20100013601A1 (en) * 2008-03-20 2010-01-21 Checkpoint Systems, Inc. Applique Nodes for Performance and Functionality Enhancement in Radio Frequency Identification Systems
US20120306651A1 (en) * 2011-06-01 2012-12-06 Jobsite Resources Llc Mobile perimeter access security system
US9659336B2 (en) 2012-04-10 2017-05-23 Bags, Inc. Mobile baggage dispatch system and method

Families Citing this family (349)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010016825A1 (en) * 1993-06-08 2001-08-23 Pugliese, Anthony V. Electronic ticketing and reservation system and method
US6362737B1 (en) 1998-06-02 2002-03-26 Rf Code, Inc. Object Identification system with adaptive transceivers and methods of operation
US7054271B2 (en) 1996-12-06 2006-05-30 Ipco, Llc Wireless network system and method for providing same
US8982856B2 (en) 1996-12-06 2015-03-17 Ipco, Llc Systems and methods for facilitating wireless network communication, satellite-based wireless network systems, and aircraft-based wireless network systems, and related methods
IL120684A (en) * 1997-04-16 2009-08-03 Handelman Doron Entertainment system
US6504864B1 (en) 1997-04-22 2003-01-07 Silicon Laboratories Inc. Digital access arrangement circuitry and method for connecting to phone lines having a second order DC holding circuit
US5870046A (en) 1997-04-22 1999-02-09 Silicon Laboratories Inc. Analog isolation system with digital communication across a capacitive barrier
US6144326A (en) 1997-04-22 2000-11-07 Silicon Laboratories, Inc. Digital isolation system with ADC offset calibration
US6480602B1 (en) 1997-04-22 2002-11-12 Silicon Laboratories, Inc. Ring-detect interface circuitry and method for a communication system
US6498825B1 (en) 1997-04-22 2002-12-24 Silicon Laboratories Inc. Digital access arrangement circuitry and method for connecting to phone lines having a DC holding circuit with programmable current limiting
US6389134B1 (en) 1997-04-22 2002-05-14 Silicon Laboratories, Inc. Call progress monitor circuitry and method for a communication system
US6587560B1 (en) * 1997-04-22 2003-07-01 Silicon Laboratories Inc. Low voltage circuits powered by the phone line
US6516024B1 (en) 1997-04-22 2003-02-04 Silicon Laboratories Inc. Digital access arrangement circuitry and method for connecting to phone lines having a DC holding circuit with low distortion and current limiting
US6442271B1 (en) * 1997-04-22 2002-08-27 Silicon Laboratories, Inc. Digital isolation system with low power mode
US6456712B1 (en) 1997-04-22 2002-09-24 Silicon Laboratories Inc. Separation of ring detection functions across isolation barrier for minimum power
US6339048B1 (en) * 1999-12-23 2002-01-15 Elementis Specialties, Inc. Oil and oil invert emulsion drilling fluids with improved anti-settling properties
US6359983B1 (en) 1997-04-22 2002-03-19 Silicon Laboratories, Inc. Digital isolation system with data scrambling
US6408034B1 (en) 1997-04-22 2002-06-18 Silicon Laboratories, Inc. Framed delta sigma data with unlikely delta sigma data patterns
US6430229B1 (en) 1997-04-22 2002-08-06 Silicon Laboratories Inc. Capacitive isolation system with digital communication and power transfer
US6385235B1 (en) 1997-04-22 2002-05-07 Silicon Laboratories, Inc. Direct digital access arrangement circuitry and method for connecting to phone lines
US6289070B1 (en) 1997-04-22 2001-09-11 Silicon Laboratories, Inc. Digital isolation system with ADC offset calibration including coarse offset
US6167134A (en) * 1997-04-22 2000-12-26 Silicon Laboratories, Inc. External resistor and method to minimize power dissipation in DC holding circuitry for a communication system
US6442213B1 (en) * 1997-04-22 2002-08-27 Silicon Laboratories Inc. Digital isolation system with hybrid circuit in ADC calibration loop
US6137827A (en) * 1997-04-22 2000-10-24 Silicon Laboratories, Inc. Isolation system with digital communication across a capacitive barrier
EP0879617B1 (en) * 1997-05-21 2003-04-16 Schneider (Europe) GmbH Pressure monitoring guide wire and method for manufacturing such a guide wire
DE19738323C1 (en) * 1997-09-02 1999-02-04 Siemens Ag Locating transponder based remote control unit used for car central locking system
US6118789A (en) 1998-02-19 2000-09-12 Micron Technology, Inc. Method of addressing messages and communications system
US6072801A (en) 1998-02-19 2000-06-06 Micron Technology, Inc. Method of addressing messages, method of establishing wireless communications, and communications system
USRE43382E1 (en) 1998-02-19 2012-05-15 Round Rock Research, Llc Method of addressing messages and communications systems
US6061344A (en) 1998-02-19 2000-05-09 Micron Technology, Inc. Method of addressing messages and communications system
US6275476B1 (en) * 1998-02-19 2001-08-14 Micron Technology, Inc. Method of addressing messages and communications system
US6609656B1 (en) * 1998-03-27 2003-08-26 Micron Technology, Inc. Method and system for identifying lost or stolen devices
US6075973A (en) * 1998-05-18 2000-06-13 Micron Technology, Inc. Method of communications in a backscatter system, interrogator, and backscatter communications system
US6879962B1 (en) * 1998-05-24 2005-04-12 Joseph D. Smith Logistics system and method
JP2000011055A (en) * 1998-06-19 2000-01-14 Fujitsu Ltd Traveler management system
US6437692B1 (en) 1998-06-22 2002-08-20 Statsignal Systems, Inc. System and method for monitoring and controlling remote devices
US6914893B2 (en) 1998-06-22 2005-07-05 Statsignal Ipc, Llc System and method for monitoring and controlling remote devices
US8410931B2 (en) 1998-06-22 2013-04-02 Sipco, Llc Mobile inventory unit monitoring systems and methods
US6891838B1 (en) 1998-06-22 2005-05-10 Statsignal Ipc, Llc System and method for monitoring and controlling residential devices
US6109530A (en) * 1998-07-08 2000-08-29 Motorola, Inc. Integrated circuit carrier package with battery coin cell
US6192222B1 (en) * 1998-09-03 2001-02-20 Micron Technology, Inc. Backscatter communication systems, interrogators, methods of communicating in a backscatter system, and backscatter communication methods
US6513015B2 (en) * 1998-09-25 2003-01-28 Fujitsu Limited System and method for customer recognition using wireless identification and visual data transmission
US7190332B1 (en) * 1998-12-21 2007-03-13 Roke Manor Research Limited Acoustically activated marketing device
FR2789493B1 (en) * 1999-02-09 2001-03-09 Gemplus Card Int METHOD FOR DETECTION OF PORTABLE OBJECTS AND IMPLEMENTATION SYSTEM
US6603391B1 (en) * 1999-03-09 2003-08-05 Micron Technology, Inc. Phase shifters, interrogators, methods of shifting a phase angle of a signal, and methods of operating an interrogator
US7592898B1 (en) * 1999-03-09 2009-09-22 Keystone Technology Solutions, Llc Wireless communication systems, interrogators and methods of communicating within a wireless communication system
US6356764B1 (en) * 1999-03-09 2002-03-12 Micron Technology, Inc. Wireless communication systems, interrogators and methods of communicating within a wireless communication system
US7650425B2 (en) 1999-03-18 2010-01-19 Sipco, Llc System and method for controlling communication between a host computer and communication devices associated with remote devices in an automated monitoring system
US6611232B1 (en) * 1999-03-18 2003-08-26 Robert L. Stanley Lock box locator
JP2002543500A (en) * 1999-04-27 2002-12-17 アイスリーイー・ホールディングス・エルエルシー Remote ordering system
JP2001036545A (en) * 1999-05-17 2001-02-09 Sony Corp Information processing unit, its method, information processing system and medium
SE516100C2 (en) * 1999-05-26 2001-11-19 Henry Duhs Arrangement with mobile communication unit and RFID circuit to provide a service
WO2001001366A2 (en) 1999-06-25 2001-01-04 Telemonitor, Inc. Smart remote monitoring system and method
US6714121B1 (en) 1999-08-09 2004-03-30 Micron Technology, Inc. RFID material tracking method and apparatus
US6363239B1 (en) * 1999-08-11 2002-03-26 Eastman Kodak Company Print having attached audio data storage and method of providing same
US6414626B1 (en) * 1999-08-20 2002-07-02 Micron Technology, Inc. Interrogators, wireless communication systems, methods of operating an interrogator, methods of operating a wireless communication system, and methods of determining range of a remote communication device
US7889052B2 (en) * 2001-07-10 2011-02-15 Xatra Fund Mx, Llc Authorizing payment subsequent to RF transactions
US7143049B2 (en) * 1999-09-10 2006-11-28 Siemens Vdo Automotive Ag Method and system for registering tickets
PT1210693E (en) * 1999-09-10 2004-03-31 Siemens Transit Telematic Systems Ag PROCESS AND SYSTEM FOR TICKET REGISTRATION
US6608551B1 (en) * 1999-09-13 2003-08-19 Intermec Ip Corp Low-cost radio replacement utilizing RFID technology
US7109869B2 (en) * 1999-09-28 2006-09-19 Clifford Sweatte Method and system for facility security
US7515055B2 (en) * 1999-09-28 2009-04-07 Clifford Sweatte Method and system for airport security
US6674367B2 (en) 1999-09-28 2004-01-06 Clifford Sweatte Method and system for airport and building security
US6335688B1 (en) * 1999-09-28 2002-01-01 Clifford Sweatte Method and system for airport security
US6307471B1 (en) * 1999-12-01 2001-10-23 Ensure Technologies, Inc. Radio based proximity token with multiple antennas
US6617962B1 (en) * 2000-01-06 2003-09-09 Samsys Technologies Inc. System for multi-standard RFID tags
US6785739B1 (en) 2000-02-23 2004-08-31 Eastman Kodak Company Data storage and retrieval playback apparatus for a still image receiver
US6509836B1 (en) * 2000-03-31 2003-01-21 Georgia Tech Research Corporation Smart reflection antenna system and method
JP2001297139A (en) * 2000-04-12 2001-10-26 Hudson Soft Co Ltd Baggage management system
GB2362070B (en) 2000-05-05 2004-06-16 Nokia Mobile Phones Ltd Communication devices and method of communication
US7599847B2 (en) 2000-06-09 2009-10-06 Airport America Automated internet based interactive travel planning and management system
US10142836B2 (en) 2000-06-09 2018-11-27 Airport America, Llc Secure mobile device
US7315567B2 (en) * 2000-07-10 2008-01-01 Motorola, Inc. Method and apparatus for partial interference cancellation in a communication system
CA2419548A1 (en) * 2000-08-14 2002-02-21 Adbeep.Com, Llc Method and apparatus for displaying advertising indicia on a wireless device
US7176849B1 (en) * 2000-08-15 2007-02-13 Agere Systems Inc. Wireless security badge
US6519328B1 (en) * 2000-08-28 2003-02-11 Telenetwork, Inc. Variable low frequency offset, differential, OOK, high-speed twisted pair communication using telephone load coils
GB2366945B (en) * 2000-09-12 2004-07-14 Iprox Ltd Baggage and passenger monitoring system
US6807458B2 (en) * 2000-09-20 2004-10-19 Steve Quackenbush Baggage transportation security system
US6512964B1 (en) 2000-09-20 2003-01-28 Baggagedirect.Com, Inc. Baggage transportation method
US7979057B2 (en) * 2000-10-06 2011-07-12 S.F. Ip Properties 62 Llc Third-party provider method and system
US6883710B2 (en) * 2000-10-11 2005-04-26 Amerasia International Technology, Inc. Article tracking system and method
US7098793B2 (en) * 2000-10-11 2006-08-29 Avante International Technology, Inc. Tracking system and method employing plural smart tags
US7508308B2 (en) * 2000-10-16 2009-03-24 Avante International Technology, Inc. Tracking apparatus and method, as for an exhibition
US7813934B1 (en) 2000-10-16 2010-10-12 Avante International Technology, Inc. Tracking apparatus and method, as for an exhibition
US7171369B1 (en) * 2000-11-08 2007-01-30 Delta Air Lines, Inc. Method and system for providing dynamic and real-time air travel information
US20020080198A1 (en) * 2000-11-14 2002-06-27 Safetzone Technologies Corporation System for real-time location of people in a fixed environment
DE10062726C1 (en) * 2000-12-15 2002-02-14 Deutsch Zentr Luft & Raumfahrt Method of conducting check-in process in airport involves user calling up check-in service directly from mobile communications terminal via server when within range of beacon
EP1220163A1 (en) * 2000-12-29 2002-07-03 EM Microelectronic-Marin SA Passage detection system for individuals or objects through an entrance-exit with a limited space
DE10065684A1 (en) * 2000-12-29 2002-07-18 Aladdin Knowledge Systems Gmbh System and method for granting permission to run a program installed on a computer
EP1221678A1 (en) * 2001-01-09 2002-07-10 Telectronic SA Receiver for sensing an electromagnetic signal and device using such a receiver
US20020107714A1 (en) * 2001-02-06 2002-08-08 Whitlock Steve Alexander Method and system fo transferring connecting baggage
EP1235188A1 (en) * 2001-02-21 2002-08-28 Häni- Prolectron AG Method for registering tickets
US6788199B2 (en) * 2001-03-12 2004-09-07 Eureka Technology Partners, Llc Article locator system
US20020170962A1 (en) * 2001-03-22 2002-11-21 Koninklijke Philips Electronics N.V. Subsidizing public transportation through electronic coupons
US6873258B2 (en) * 2001-04-10 2005-03-29 Telcordia Technologies, Inc. Location aware services infrastructure
US20020169643A1 (en) * 2001-05-11 2002-11-14 Statsignal Systems, Inc. System and method for remotely processing reservations
JP2002373217A (en) * 2001-06-14 2002-12-26 Ids Japan:Kk Guiding system for traveler moving space such as airport
US7737861B2 (en) * 2001-06-19 2010-06-15 Paxflow Holdings Pte Ltd. Location, communication and tracking systems
WO2002103641A1 (en) * 2001-06-20 2002-12-27 Dna Group Limited Method and apparatus for facilitating the flow of pedestrian traffic
US20020198731A1 (en) * 2001-06-26 2002-12-26 Barnes Jessica M. Method and apparatus for processing an international passenger
US6961000B2 (en) * 2001-07-05 2005-11-01 Amerasia International Technology, Inc. Smart tag data encoding method
JP4187953B2 (en) 2001-08-15 2008-11-26 キャボットスーパーメタル株式会社 Method for producing nitrogen-containing metal powder
EP1419486A1 (en) * 2001-08-17 2004-05-19 Siemens Transit Telematic Systems AG Method and circuit arrangement for trigger telegram recognition and selection
US6937154B2 (en) 2001-08-21 2005-08-30 Tabula Rasa, Inc. Method and apparatus for facilitating personal attention via wireless links
US20030043042A1 (en) * 2001-08-21 2003-03-06 Tabula Rasa, Inc. Method and apparatus for facilitating personal attention via wireless networks
US6993298B2 (en) * 2001-09-07 2006-01-31 Siemens Energy & Automation, Inc. Programmable controller with RF wireless interface
US7158030B2 (en) * 2001-09-19 2007-01-02 Avante International Technology Medical assistance and tracking system and method employing smart tags
US7090126B2 (en) * 2001-10-22 2006-08-15 Maximus, Inc. Method and apparatus for providing heightened airport security
US20060243799A1 (en) * 2001-10-22 2006-11-02 Maximus, Inc., Method and apparatus for providing heightened airport security
US7480501B2 (en) 2001-10-24 2009-01-20 Statsignal Ipc, Llc System and method for transmitting an emergency message over an integrated wireless network
US8489063B2 (en) 2001-10-24 2013-07-16 Sipco, Llc Systems and methods for providing emergency messages to a mobile device
US7424527B2 (en) 2001-10-30 2008-09-09 Sipco, Llc System and method for transmitting pollution information over an integrated wireless network
EP1308864A1 (en) * 2001-11-02 2003-05-07 Hewlett-Packard Company Passenger management system and method and electronic device
US7061383B2 (en) * 2001-11-15 2006-06-13 United Air Lines, Inc. Radio frequency check-in
US20050078006A1 (en) * 2001-11-20 2005-04-14 Hutchins J. Marc Facilities management system
US6951305B2 (en) * 2001-11-21 2005-10-04 Goliath Solutions, Llc. Advertising compliance monitoring system
US6837427B2 (en) * 2001-11-21 2005-01-04 Goliath Solutions, Llc. Advertising compliance monitoring system
US7374096B2 (en) 2001-11-21 2008-05-20 Goliath Solutions, Llc Advertising compliance monitoring system
US7023356B2 (en) 2001-11-26 2006-04-04 Aero-Vision Technologies, Inc. System and method for monitoring individuals and objects associated with wireless identification tags
US6759972B2 (en) 2001-11-27 2004-07-06 Digicomp Research Corporation Tour group notification method
US20050083171A1 (en) * 2001-12-10 2005-04-21 Sharon Hamilton Security systems
AU2002365052A1 (en) * 2001-12-21 2003-07-30 Gregg Panek System for separate shipping of passenger bagagge
EP1324626A3 (en) * 2001-12-28 2003-12-17 Matsushita Electric Industrial Co., Ltd. Control system and method for a wireless communications terminal
EP1470613A4 (en) * 2002-01-09 2005-10-05 Meadwestvaco Corp Intelligent station using multiple rf antennae and inventory control system and method incorporating same
US8321302B2 (en) * 2002-01-23 2012-11-27 Sensormatic Electronics, LLC Inventory management system
US8339265B2 (en) 2002-01-09 2012-12-25 Sensormatic Electronics, Llc. Method of assigning and deducing the location of articles detected by multiple RFID antennae
US20030141962A1 (en) * 2002-01-25 2003-07-31 Bernard Barink RFID systems - antenna system and software method to spatially locate transponders
GB0202123D0 (en) * 2002-01-30 2002-03-20 Knight Tony Passenger check-in and monitoring system
US20030141411A1 (en) * 2002-01-31 2003-07-31 Ashish Pandya Novel method to secure airline travel
US20030225612A1 (en) * 2002-02-12 2003-12-04 Delta Air Lines, Inc. Method and system for implementing security in the travel industry
IE20030152A1 (en) * 2002-03-05 2003-09-17 Internat Airtag Ltd A communication system
US20030172083A1 (en) * 2002-03-07 2003-09-11 Ncr Corporation System and method of processing passenger requests
US20050113138A1 (en) * 2002-03-18 2005-05-26 Greg Mendolia RF ID tag reader utlizing a scanning antenna system and method
JP3807496B2 (en) * 2002-03-18 2006-08-09 富士通株式会社 Package delivery destination management method, apparatus and program
JP2006508412A (en) * 2002-03-18 2006-03-09 イル・ガット・インコーポレーテッド System and method for monitoring and tracking individuals
JP4016691B2 (en) * 2002-03-29 2007-12-05 三菱電機株式会社 Boarding management system
AU2002344944A1 (en) * 2002-05-13 2003-11-11 Lyngso Industri A/S Aviation handling quality measurement
KR20030089627A (en) * 2002-05-16 2003-11-22 여태순 Enter and leave managing system
US6933849B2 (en) 2002-07-09 2005-08-23 Fred Sawyer Method and apparatus for tracking objects and people
US20040036597A1 (en) * 2002-08-20 2004-02-26 Bluespan, L.L.C. Directional finding system implementing a rolling code
US20040044956A1 (en) * 2002-08-27 2004-03-04 Silicon Valley Micro C Corporation Intelligent document
US20040049733A1 (en) * 2002-09-09 2004-03-11 Eastman Kodak Company Virtual annotation of a recording on an archival media
AU2003275297A1 (en) * 2002-09-27 2004-04-23 Hill-Rom Services, Inc. Universal communications, monitoring, tracking, and control system for a healthcare facility
US7233498B2 (en) 2002-09-27 2007-06-19 Eastman Kodak Company Medium having data storage and communication capabilities and method for forming same
US20040062016A1 (en) * 2002-09-27 2004-04-01 Eastman Kodak Company Medium having data storage and communication capabilites and method for forming same
US6900762B2 (en) * 2002-09-30 2005-05-31 Lucent Technologies Inc. Methods and apparatus for location determination based on dispersed radio frequency tags
JP2004132890A (en) * 2002-10-11 2004-04-30 Fujitsu Component Ltd Noncontact ic card reader/writer apparatus, noncontact ic card, input apparatus, and noncontact method for computing position of ic card
US7962361B2 (en) 2002-11-07 2011-06-14 Novitaz Customer relationship management system for physical locations
US8600804B2 (en) 2002-11-07 2013-12-03 Novitaz, Inc. Customer relationship management system for physical locations
US7110925B2 (en) * 2002-11-14 2006-09-19 Accenture Global Services Gmbh Security checkpoint simulation
US20040098272A1 (en) * 2002-11-14 2004-05-20 James Kapsis Computer based system for tracking articles
US20040100390A1 (en) * 2002-11-19 2004-05-27 Safetzone Technologies Corp. Queue management system and method
AU2003286286A1 (en) * 2002-12-06 2004-06-30 Koninklijke Philips Electronics N.V. Apparatus and method for automated positioning of a device
US7231355B2 (en) * 2002-12-06 2007-06-12 The Boeing Company Method and apparatus for correlating and tracking passengers and baggage for a trackable passenger trip
CN1720553A (en) * 2002-12-06 2006-01-11 皇家飞利浦电子股份有限公司 System and method for providing passenger security and convenience in a public transportation terminal
EP1429570A1 (en) * 2002-12-13 2004-06-16 Abb Research Ltd. On-site localisation system and method
US7802724B1 (en) 2002-12-20 2010-09-28 Steven Paul Nohr Identifications and communications methods
US7151454B2 (en) * 2003-01-02 2006-12-19 Covi Technologies Systems and methods for location of objects
US6829989B2 (en) * 2003-01-22 2004-12-14 Golf Gifts & Gallery Inc. Apparatus and method for marking a golf ball
US7173532B2 (en) * 2003-03-27 2007-02-06 Xegesis, Llc Intelligent controlled entry-exit system
US20040199411A1 (en) * 2003-04-04 2004-10-07 Bertram Jeffrey Mark Method and system for rebooking a passenger
US20040204968A1 (en) * 2003-04-04 2004-10-14 Delta Air Lines, Inc. Method and system for providing rebooking information to passengers
US8378841B2 (en) * 2003-04-09 2013-02-19 Visible Assets, Inc Tracking of oil drilling pipes and other objects
US8026819B2 (en) * 2005-10-02 2011-09-27 Visible Assets, Inc. Radio tag and system
US20100033330A1 (en) * 2003-04-09 2010-02-11 Visible Assets, Inc. Auditable security for cargo containers and other repositories
US8681000B2 (en) * 2003-04-09 2014-03-25 Visible Assets, Inc. Low frequency inductive tagging for lifecycle management
JP4337383B2 (en) * 2003-04-10 2009-09-30 セイコーエプソン株式会社 Equipment capable of mounting consumable containers
WO2004092999A2 (en) * 2003-04-17 2004-10-28 Symbol Technologies, Inc. Multimode wireless local area network/radio frequency identification asset tag
WO2004105356A2 (en) * 2003-05-19 2004-12-02 Board Of Control Of Michigan Technological University Wireless local positioning system
DE10325909A1 (en) * 2003-06-05 2005-01-05 Deutsche Post Ag Method and device for securing objects
NZ544088A (en) * 2003-06-17 2008-07-31 United Security Appl Id Inc Electronic security system for monitoring and recording activity and data relating to institutions and clients thereof
US20090057399A1 (en) * 2003-06-17 2009-03-05 United Security Applications Id, Inc. Electronic security system for monitoring and recording activity and data relating to institutions and clients thereof
JP2006527892A (en) * 2003-06-17 2006-12-07 ユナイテッド・セキュリティー・アプリケーションズ・アイディー、インク Electronic security system for monitoring and recording human-related activities and data
US20060145812A1 (en) * 2003-06-17 2006-07-06 United Security Applications Id, Inc. Electronic security system for monitoring and recording activity and data relating to persons or cargo
CN100530226C (en) 2003-07-22 2009-08-19 诺基亚公司 Reader device for radio frequency identification transponder with transponder functionality
US6943729B2 (en) * 2003-10-01 2005-09-13 S5 Wireless, Inc. Method and system for time difference of arrival (TDOA) location services
US20070080801A1 (en) * 2003-10-16 2007-04-12 Weismiller Matthew W Universal communications, monitoring, tracking, and control system for a healthcare facility
US20050097010A1 (en) * 2003-10-31 2005-05-05 Battelle Memorial Institute System and method for remote inventory management
US7145464B2 (en) * 2003-11-19 2006-12-05 Eastman Kodak Company Data collection device
US7109986B2 (en) * 2003-11-19 2006-09-19 Eastman Kodak Company Illumination apparatus
US7044371B2 (en) * 2003-11-20 2006-05-16 Southwest Airlines Co. Passenger monitoring system and method
US6989749B2 (en) * 2003-11-21 2006-01-24 The United States Of America As Represented By The Secretary Of The Navy Electronic check out system
US7009494B2 (en) * 2003-11-21 2006-03-07 Eastman Kodak Company Media holder having communication capabilities
US7818190B1 (en) 2003-12-09 2010-10-19 Kampgrounds of America, Inc. Camping reservation system, method and program
US8517265B2 (en) * 2003-12-18 2013-08-27 Altierre Corporation Error free method for wireless display tag (WDT)
US8313025B2 (en) * 2003-12-18 2012-11-20 Altierre Corporation Wireless display tag (WDT) using active and backscatter transceivers
KR100556438B1 (en) * 2004-01-02 2006-03-03 엘지전자 주식회사 Remote Controller of The Display Device and Method for Controlling of The Same
IL159828A0 (en) * 2004-01-12 2005-11-20 Elbit Systems Ltd System and method for identifying a threat associated person among a crowd
ES2290667T3 (en) 2004-01-23 2008-02-16 Nokia Corporation METHOD, DEVICE AND SYSTEM FOR INFORMATION OF AUTOMATED CONTEXT FROM SELECTIVE DATA PROVIDED BY MEANS OF IDENTIFICATION.
DE102004004587B4 (en) * 2004-01-29 2005-12-22 Rathgeber, Thomas, Dr. Device and method for retrieving objects
US20050187812A1 (en) * 2004-02-25 2005-08-25 International Business Machines Corporation Method, system, and storage medium for predicting passenger flow at a transportation facility
US8031650B2 (en) 2004-03-03 2011-10-04 Sipco, Llc System and method for monitoring remote devices with a dual-mode wireless communication protocol
US7756086B2 (en) 2004-03-03 2010-07-13 Sipco, Llc Method for communicating in dual-modes
US7385476B2 (en) * 2004-03-11 2008-06-10 Symbol Technologies, Inc. Method and system for communicating data to a wireless access point
US8676614B2 (en) * 2004-03-12 2014-03-18 Amr Corporation Automated airlines reservations system
EP1725976B2 (en) 2004-03-17 2013-04-03 Nokia Corporation Continuous data provision by radio frequency identification (rfid) transponders
ATE428994T1 (en) 2004-03-19 2009-05-15 Nokia Corp DETECTOR LOGIC AND RADIO IDENTIFICATION DEVICE AND METHOD FOR IMPROVING TERMINAL OPERATION
US6929218B1 (en) * 2004-03-29 2005-08-16 The Boeing Company Modularized integrated aircraft seat structure
US7126470B2 (en) * 2004-03-31 2006-10-24 Harris Corporation Wireless ad-hoc RFID tracking system
US20050258937A1 (en) * 2004-05-05 2005-11-24 Trenstar, Inc. Radio frequency identification asset management system and method
US7466232B2 (en) * 2004-05-05 2008-12-16 Trenstar Tracking Solutions, Inc. Radio frequency identification asset management system and method
US7633392B2 (en) * 2004-05-05 2009-12-15 General Electric Company Radio frequency identification asset management system, and computer program product
US20050258231A1 (en) * 2004-05-18 2005-11-24 Keith Wiater Cruise ship passenger and baggage processing system
US7327251B2 (en) * 2004-05-28 2008-02-05 Corbett Jr Bradford G RFID system for locating people, objects and things
US20070008138A1 (en) * 2004-07-20 2007-01-11 Precision Dynamics Corporation Coordinated identification of persons and/or articles via radio frequency identification cross-identification
US20060017541A1 (en) * 2004-07-22 2006-01-26 Nguyen Martin K Tracking by radio frequency identification
EP1619602B1 (en) * 2004-07-24 2006-12-13 Siemens VDO Automotive AG Method for the registration of tickets and corresponding electronic ticket
FR2874443B1 (en) * 2004-08-17 2006-12-01 Franklin Devaux SYSTEM FOR ENHANCED SECURITY OF PASSENGERS FOR THEIR BOARDING ABOVE A MEANS OF TRANSPORT
US7342497B2 (en) * 2004-08-26 2008-03-11 Avante International Technology, Inc Object monitoring, locating, and tracking system employing RFID devices
US8174383B1 (en) 2004-08-26 2012-05-08 Avante International Technology, Inc. System and method for operating a synchronized wireless network
US7319397B2 (en) * 2004-08-26 2008-01-15 Avante International Technology, Inc. RFID device for object monitoring, locating, and tracking
US7423535B2 (en) * 2004-08-26 2008-09-09 Avante International Technology, Inc. Object monitoring, locating, and tracking method employing RFID devices
US7839289B2 (en) * 2004-08-26 2010-11-23 Avante International Technology, Inc. Object monitoring, locating, and tracking system and method employing RFID devices
US8035482B2 (en) * 2004-09-07 2011-10-11 Eastman Kodak Company System for updating a content bearing medium
EP1844455A4 (en) * 2004-09-28 2009-02-11 Visible Assets Inc Rf tags for tracking and locating travel bags
US7359717B2 (en) * 2004-09-30 2008-04-15 International Business Machines Corporation Method for transmitting an assignment through wireless transmission
US20060095277A1 (en) * 2004-10-29 2006-05-04 Noonan Eric D Tracking system
GB2419776B (en) * 2004-10-29 2010-01-06 Salem Automation Ltd Tracking apparatus
US7614556B2 (en) * 2004-11-05 2009-11-10 Goliath Solutions, Llc Distributed RFID antenna array utilizing circular polarized helical antennas
US20060163350A1 (en) * 2005-01-11 2006-07-27 Melton Michael N Managing RFID tags using an RFID-enabled cart
EP1839287A1 (en) * 2005-01-14 2007-10-03 Matthew Henderson A transponder bolt seal and a housing for a transponder
JP4808409B2 (en) * 2005-01-14 2011-11-02 株式会社日立製作所 Sensor network system, sensor data search method and program
WO2006081206A1 (en) 2005-01-25 2006-08-03 Sipco, Llc Wireless network protocol systems and methods
US7274294B2 (en) * 2005-01-26 2007-09-25 Rf Technologies, Inc. Mobile locator system and method
US7365645B2 (en) * 2005-01-26 2008-04-29 Rf Technologies, Inc. Mobile locator system and method with wander management
US7453347B1 (en) * 2005-02-15 2008-11-18 Ncr Corporation System for displaying an information package
US7265675B1 (en) 2005-03-01 2007-09-04 Alien Technology Corporation Multistatic antenna configuration for radio frequency identification (RFID) systems
JP4885463B2 (en) * 2005-03-03 2012-02-29 株式会社日立製作所 Sensor network system, sensor data processing method and program
US7333018B2 (en) * 2005-07-25 2008-02-19 Honeywell International Inc. Asset location system with enhanced accuracy
US8880047B2 (en) * 2005-08-03 2014-11-04 Jeffrey C. Konicek Realtime, location-based cell phone enhancements, uses, and applications
US8295851B2 (en) * 2005-08-03 2012-10-23 Michael Edward Finnegan Realtime, interactive and geographically defined computerized personal matching systems and methods
US7649125B2 (en) * 2005-08-31 2010-01-19 Kimberly-Clark Worldwide, Inc. Method of detecting the presence of an insult in an absorbent article and device for detecting the same
WO2007032069A1 (en) * 2005-09-14 2007-03-22 Ajinomoto Co., Inc. Reader/writer, information reading method and information reading program
US9069933B1 (en) 2005-09-28 2015-06-30 Visible Assets, Inc. Secure, networked portable storage device
MY149287A (en) 2005-09-30 2013-08-15 Inventio Ag Elevator installation operating method for transporting elevator users
US7541926B2 (en) * 2005-10-05 2009-06-02 Redxdefense, Llc Visitor control and tracking system
US7327262B2 (en) * 2005-10-12 2008-02-05 Mantic Point Solutions Limited System and method for electronic article surveillance
US20070126585A1 (en) * 2005-12-06 2007-06-07 Symbol Technologies, Inc. System integration of RFID and MIMO technologies
US20100063888A1 (en) * 2005-12-15 2010-03-11 United Security Applications Id, Inc. Identity verification system for monitoring and authorizing transactions
JP5087222B2 (en) * 2005-12-26 2012-12-05 株式会社リコー IC tag reader and / or writer and antenna unit thereof
FR2896885B1 (en) * 2006-01-27 2008-05-30 Franck Lesueur LOCATION BY RADIO WAVE OF A PERSON IN AN ENCLOSURE
US7495560B2 (en) * 2006-05-08 2009-02-24 Corning Cable Systems Llc Wireless picocellular RFID systems and methods
US8472767B2 (en) * 2006-05-19 2013-06-25 Corning Cable Systems Llc Fiber optic cable and fiber optic cable assembly for wireless access
US20070292136A1 (en) * 2006-06-16 2007-12-20 Michael Sauer Transponder for a radio-over-fiber optical fiber cable
US8115650B2 (en) * 2006-07-11 2012-02-14 PSST Mobile Equipment Ltd. - Richard Shervey Radio frequency identification based personnel safety system
JP4206108B2 (en) * 2006-07-28 2009-01-07 東芝テック株式会社 Wireless tag reader / writer
US20080036601A1 (en) * 2006-08-11 2008-02-14 Thompson Louis H Radio frequency integration platform and network therefor
US7627250B2 (en) 2006-08-16 2009-12-01 Corning Cable Systems Llc Radio-over-fiber transponder with a dual-band patch antenna system
US7310070B1 (en) 2006-08-23 2007-12-18 Goliath Solutions, Llc Radio frequency identification shelf antenna with a distributed pattern for localized tag detection
US8587406B2 (en) * 2006-09-01 2013-11-19 Intermec Ip Corp. RFID tags with orthogonal communication capabilities, and associated systems
WO2008027622A2 (en) 2006-09-01 2008-03-06 Intermec Ip Corp. Rfid tags with cdma communication capabilities
WO2008027619A2 (en) * 2006-09-01 2008-03-06 Intermec Ip Corp. Rfid tag system with block coding, such as space-time block coding
US7787823B2 (en) 2006-09-15 2010-08-31 Corning Cable Systems Llc Radio-over-fiber (RoF) optical fiber cable system with transponder diversity and RoF wireless picocellular system using same
US7848654B2 (en) 2006-09-28 2010-12-07 Corning Cable Systems Llc Radio-over-fiber (RoF) wireless picocellular system with combined picocells
FI118833B (en) * 2006-10-12 2008-03-31 Kone Corp Monitoring systems
US7885763B2 (en) * 2006-12-01 2011-02-08 Hand Held Products, Inc. Apparatus and methods for tracking movement of persons
US8873585B2 (en) 2006-12-19 2014-10-28 Corning Optical Communications Wireless Ltd Distributed antenna system for MIMO technologies
US8120463B2 (en) * 2007-01-04 2012-02-21 Lockheed Martin Corporation RFID protocol for improved tag-reader communications integrity
US7973644B2 (en) 2007-01-30 2011-07-05 Round Rock Research, Llc Systems and methods for RFID tag arbitration where RFID tags generate multiple random numbers for different arbitration sessions
US8111998B2 (en) 2007-02-06 2012-02-07 Corning Cable Systems Llc Transponder systems and methods for radio-over-fiber (RoF) wireless picocellular systems
US8004409B2 (en) * 2007-02-13 2011-08-23 Physical Optics Corporation Wireless personal information carrier having logic for connecting a battery only during data transfers
US8040221B2 (en) * 2007-05-02 2011-10-18 The Boeing Company Mobile radio frequency identification reader
US8134452B2 (en) * 2007-05-30 2012-03-13 Round Rock Research, Llc Methods and systems of receiving data payload of RFID tags
AU2008261557A1 (en) * 2007-06-15 2008-12-18 Matthew Henderson A transponder bolt seal and a housing for a transponder
US7859416B2 (en) * 2007-06-21 2010-12-28 Round Rock Research, Llc Method and system of attaching a RFID tag to an object
US7950571B2 (en) * 2007-07-02 2011-05-31 Siemens Aktiengesellschaft Electronic boarding pass
US20100054746A1 (en) 2007-07-24 2010-03-04 Eric Raymond Logan Multi-port accumulator for radio-over-fiber (RoF) wireless picocellular systems
US7916025B2 (en) * 2007-08-10 2011-03-29 Lockwinn Technology Intelligent luggage tag
US20090051501A1 (en) * 2007-08-20 2009-02-26 Micron Technology, Inc. Methods and systems of using radio frequency identification tags
US20090058648A1 (en) * 2007-08-29 2009-03-05 Micron Technology, Inc. Methods and systems of using rfid tags in emergency situations
US8175459B2 (en) 2007-10-12 2012-05-08 Corning Cable Systems Llc Hybrid wireless/wired RoF transponder and hybrid RoF communication system using same
US20090106275A1 (en) * 2007-10-22 2009-04-23 Liyun Zhang Method and system for screening items for transport
KR20090052411A (en) * 2007-11-21 2009-05-26 엘지이노텍 주식회사 Position tracking system using near field radio frequency communication
US8644844B2 (en) 2007-12-20 2014-02-04 Corning Mobileaccess Ltd. Extending outdoor location based services and applications into enclosed areas
KR100958239B1 (en) * 2008-03-10 2010-05-17 엘에스산전 주식회사 Rfid tag
US20090231136A1 (en) * 2008-03-12 2009-09-17 Binay Sugla Tags and tag-based systems and methods for locating and tracking objects
US20100060424A1 (en) * 2008-03-19 2010-03-11 Checkpoint Systems, Inc. Range Extension and Multiple Access in Modulated Backscatter Systems
US20100001844A1 (en) * 2008-07-02 2010-01-07 Bahel Alex System and Method for Receiving Wireless Data
US8742891B2 (en) * 2008-07-16 2014-06-03 Morton Greene System and method for identifying a genuine printed document
US8874459B1 (en) * 2008-07-31 2014-10-28 American Airlines, Inc. System and method for providing flight data services
US20110137692A1 (en) * 2008-08-06 2011-06-09 Shaun Beheruz Sethna System and method for boarding passengers based on valuation data
US8063848B2 (en) * 2008-12-02 2011-11-22 Bae Systems Information And Electronic Systems Integration Inc. X, Ku, K band omni-directional antenna with dielectric loading
EP2394378A1 (en) 2009-02-03 2011-12-14 Corning Cable Systems LLC Optical fiber-based distributed antenna systems, components, and related methods for monitoring and configuring thereof
WO2010091004A1 (en) 2009-02-03 2010-08-12 Corning Cable Systems Llc Optical fiber-based distributed antenna systems, components, and related methods for calibration thereof
US9673904B2 (en) 2009-02-03 2017-06-06 Corning Optical Communications LLC Optical fiber-based distributed antenna systems, components, and related methods for calibration thereof
KR100999595B1 (en) * 2009-04-28 2010-12-08 (주)벨론텍 RF-integrated card system and Controllong method using the same
US20100295782A1 (en) 2009-05-21 2010-11-25 Yehuda Binder System and method for control based on face ore hand gesture detection
US20110025464A1 (en) * 2009-07-30 2011-02-03 Awarepoint Corporation Antenna Diversity For Wireless Tracking System And Method
US8548330B2 (en) 2009-07-31 2013-10-01 Corning Cable Systems Llc Sectorization in distributed antenna systems, and related components and methods
US8028903B1 (en) * 2009-09-04 2011-10-04 F3M3 Companies, Inc. System and method of pre-approving card holders for expedited security processing using emerging countries international travel approval control card
US8514069B2 (en) * 2009-11-12 2013-08-20 MTN Satellite Communications Tracking passengers on cruise ships
US8280259B2 (en) 2009-11-13 2012-10-02 Corning Cable Systems Llc Radio-over-fiber (RoF) system for protocol-independent wired and/or wireless communication
US8275265B2 (en) 2010-02-15 2012-09-25 Corning Cable Systems Llc Dynamic cell bonding (DCB) for radio-over-fiber (RoF)-based networks and communication systems and related methods
US20110268446A1 (en) 2010-05-02 2011-11-03 Cune William P Providing digital data services in optical fiber-based distributed radio frequency (rf) communications systems, and related components and methods
US9525488B2 (en) 2010-05-02 2016-12-20 Corning Optical Communications LLC Digital data services and/or power distribution in optical fiber-based distributed communications systems providing digital data and radio frequency (RF) communications services, and related components and methods
JP2013543153A (en) * 2010-05-25 2013-11-28 ナショナル・レイルロード・パッセンジャー・コーポレーション Ticketing solution
WO2012024247A1 (en) 2010-08-16 2012-02-23 Corning Cable Systems Llc Remote antenna clusters and related systems, components, and methods supporting digital data signal propagation between remote antenna units
US9252874B2 (en) 2010-10-13 2016-02-02 Ccs Technology, Inc Power management for remote antenna units in distributed antenna systems
US20120312879A1 (en) 2011-01-06 2012-12-13 John Rolin PCB Design and Card Assembly for an Active RFID Tag in Credit Card Form Factor
US8618909B1 (en) * 2011-02-15 2013-12-31 Mark Clausen Apparatus to sequence and control passenger queues
CN203504582U (en) 2011-02-21 2014-03-26 康宁光缆系统有限责任公司 Distributed antenna system and power supply apparatus for distributing electric power thereof
EP2702780A4 (en) 2011-04-29 2014-11-12 Corning Cable Sys Llc Systems, methods, and devices for increasing radio frequency (rf) power in distributed antenna systems
EP2702710A4 (en) 2011-04-29 2014-10-29 Corning Cable Sys Llc Determining propagation delay of communications in distributed antenna systems, and related components, systems and methods
CN102353934A (en) * 2011-06-29 2012-02-15 苏州科雷芯电子科技有限公司 System and device for positioning passengers in airport
WO2013148986A1 (en) 2012-03-30 2013-10-03 Corning Cable Systems Llc Reducing location-dependent interference in distributed antenna systems operating in multiple-input, multiple-output (mimo) configuration, and related components, systems, and methods
US8976022B2 (en) * 2012-04-13 2015-03-10 Khalid Hamad Motleb ALNAFISAH Mobile tracking identification system, method, and computer program product
EP2842245A1 (en) 2012-04-25 2015-03-04 Corning Optical Communications LLC Distributed antenna system architectures
ES2429417A1 (en) * 2012-05-11 2013-11-14 Universidad Politécnica de Madrid System and method for locating objects using radio frequency identifiers
US8768565B2 (en) 2012-05-23 2014-07-01 Enterprise Holdings, Inc. Rental/car-share vehicle access and management system and method
US10515489B2 (en) 2012-05-23 2019-12-24 Enterprise Holdings, Inc. Rental/car-share vehicle access and management system and method
US20140156318A1 (en) * 2012-12-03 2014-06-05 National Railroad Passenger Corporation User interface for onboard ticket validation and collection
WO2014024192A1 (en) 2012-08-07 2014-02-13 Corning Mobile Access Ltd. Distribution of time-division multiplexed (tdm) management services in a distributed antenna system, and related components, systems, and methods
US9455784B2 (en) 2012-10-31 2016-09-27 Corning Optical Communications Wireless Ltd Deployable wireless infrastructures and methods of deploying wireless infrastructures
CN105308876B (en) 2012-11-29 2018-06-22 康宁光电通信有限责任公司 Remote unit antennas in distributing antenna system combines
US9647758B2 (en) 2012-11-30 2017-05-09 Corning Optical Communications Wireless Ltd Cabling connectivity monitoring and verification
US8744926B1 (en) * 2013-03-15 2014-06-03 Kwivo, LLC Pre-transit and post-transit facilitation of in-vehicle services
US8751646B1 (en) 2013-03-15 2014-06-10 Kwivo, LLC In-vehicle services through attendant devices, user-provided devices, and/or an in-vehicle computer system
US8972598B2 (en) 2013-03-15 2015-03-03 Kwivo, LLC In-vehicle services for user-provided devices
US8719064B1 (en) * 2013-03-15 2014-05-06 Kwivo, LLC Administration and customization platform for in-vehicle services
WO2014199384A1 (en) 2013-06-12 2014-12-18 Corning Optical Communications Wireless, Ltd. Voltage controlled optical directional coupler
WO2014199380A1 (en) 2013-06-12 2014-12-18 Corning Optical Communications Wireless, Ltd. Time-division duplexing (tdd) in distributed communications systems, including distributed antenna systems (dass)
US9247543B2 (en) 2013-07-23 2016-01-26 Corning Optical Communications Wireless Ltd Monitoring non-supported wireless spectrum within coverage areas of distributed antenna systems (DASs)
US9661781B2 (en) 2013-07-31 2017-05-23 Corning Optical Communications Wireless Ltd Remote units for distributed communication systems and related installation methods and apparatuses
EP2835788B1 (en) * 2013-08-06 2019-11-20 Skidata Ag Method for controlling entry and exit in multi-storey car parks and parking facilities
US9940663B2 (en) 2013-08-15 2018-04-10 Frank Daly Ward Indoor location mapping and wayfinding system
US9385810B2 (en) 2013-09-30 2016-07-05 Corning Optical Communications Wireless Ltd Connection mapping in distributed communication systems
US9178635B2 (en) 2014-01-03 2015-11-03 Corning Optical Communications Wireless Ltd Separation of communication signal sub-bands in distributed antenna systems (DASs) to reduce interference
US9775123B2 (en) 2014-03-28 2017-09-26 Corning Optical Communications Wireless Ltd. Individualized gain control of uplink paths in remote units in a distributed antenna system (DAS) based on individual remote unit contribution to combined uplink power
US9357551B2 (en) 2014-05-30 2016-05-31 Corning Optical Communications Wireless Ltd Systems and methods for simultaneous sampling of serial digital data streams from multiple analog-to-digital converters (ADCS), including in distributed antenna systems
US9525472B2 (en) 2014-07-30 2016-12-20 Corning Incorporated Reducing location-dependent destructive interference in distributed antenna systems (DASS) operating in multiple-input, multiple-output (MIMO) configuration, and related components, systems, and methods
US9730228B2 (en) 2014-08-29 2017-08-08 Corning Optical Communications Wireless Ltd Individualized gain control of remote uplink band paths in a remote unit in a distributed antenna system (DAS), based on combined uplink power level in the remote unit
US9602210B2 (en) 2014-09-24 2017-03-21 Corning Optical Communications Wireless Ltd Flexible head-end chassis supporting automatic identification and interconnection of radio interface modules and optical interface modules in an optical fiber-based distributed antenna system (DAS)
US9420542B2 (en) 2014-09-25 2016-08-16 Corning Optical Communications Wireless Ltd System-wide uplink band gain control in a distributed antenna system (DAS), based on per band gain control of remote uplink paths in remote units
US10659163B2 (en) 2014-09-25 2020-05-19 Corning Optical Communications LLC Supporting analog remote antenna units (RAUs) in digital distributed antenna systems (DASs) using analog RAU digital adaptors
WO2016071902A1 (en) 2014-11-03 2016-05-12 Corning Optical Communications Wireless Ltd. Multi-band monopole planar antennas configured to facilitate improved radio frequency (rf) isolation in multiple-input multiple-output (mimo) antenna arrangement
WO2016075696A1 (en) 2014-11-13 2016-05-19 Corning Optical Communications Wireless Ltd. Analog distributed antenna systems (dass) supporting distribution of digital communications signals interfaced from a digital signal source and analog radio frequency (rf) communications signals
US9729267B2 (en) 2014-12-11 2017-08-08 Corning Optical Communications Wireless Ltd Multiplexing two separate optical links with the same wavelength using asymmetric combining and splitting
WO2016098111A1 (en) 2014-12-18 2016-06-23 Corning Optical Communications Wireless Ltd. Digital- analog interface modules (da!ms) for flexibly.distributing digital and/or analog communications signals in wide-area analog distributed antenna systems (dass)
EP3235336A1 (en) 2014-12-18 2017-10-25 Corning Optical Communications Wireless Ltd. Digital interface modules (dims) for flexibly distributing digital and/or analog communications signals in wide-area analog distributed antenna systems (dass)
US9536407B2 (en) * 2014-12-30 2017-01-03 Paypal, Inc. Emergency monitoring of tagged objects
US20160249365A1 (en) 2015-02-19 2016-08-25 Corning Optical Communications Wireless Ltd. Offsetting unwanted downlink interference signals in an uplink path in a distributed antenna system (das)
US9681313B2 (en) 2015-04-15 2017-06-13 Corning Optical Communications Wireless Ltd Optimizing remote antenna unit performance using an alternative data channel
JP2017021499A (en) * 2015-07-08 2017-01-26 日立オムロンターミナルソリューションズ株式会社 Management system, combination of communication terminals for management system, and computer for management system
US9948349B2 (en) 2015-07-17 2018-04-17 Corning Optical Communications Wireless Ltd IOT automation and data collection system
US10560214B2 (en) 2015-09-28 2020-02-11 Corning Optical Communications LLC Downlink and uplink communication path switching in a time-division duplex (TDD) distributed antenna system (DAS)
US10236924B2 (en) 2016-03-31 2019-03-19 Corning Optical Communications Wireless Ltd Reducing out-of-channel noise in a wireless distribution system (WDS)
JP2018046517A (en) * 2016-09-16 2018-03-22 インターブリッジ合同会社 Autonomous small wireless device and its distributed installation method
CN110603196A (en) * 2016-12-16 2019-12-20 恩巴斯艾尔集团国际公司 Safety terminal building
JP7093485B2 (en) * 2018-01-24 2022-06-30 インターブリッジ合同会社 Autonomous small wireless device and its distributed installation method

Citations (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3750103A (en) * 1970-12-30 1973-07-31 Gen Computing Equipment Corp Electronic system employing plural processing stations for issuing airline boarding passes while effecting seat assignments, and generally for parcelling elements of an ordered set
US4075632A (en) * 1974-08-27 1978-02-21 The United States Of America As Represented By The United States Department Of Energy Interrogation, and detection system
US4247759A (en) * 1978-10-10 1981-01-27 Cubic Western Data Self-service passenger ticketing system
US4449186A (en) * 1981-10-15 1984-05-15 Cubic Western Data Touch panel passenger self-ticketing system
US4471345A (en) * 1982-03-05 1984-09-11 Sensormatic Electronics Corporation Randomized tag to portal communication system
US4926182A (en) * 1986-05-30 1990-05-15 Sharp Kabushiki Kaisha Microwave data transmission apparatus
US4931932A (en) * 1987-09-28 1990-06-05 Travelsoft, Inc. Computerized system with means to automatically clear and sell wait-listed customer reservations
US4984156A (en) * 1986-12-05 1991-01-08 Omron Tateisi Electronics Co. Automatic checkin apparatus
US5010240A (en) * 1989-04-11 1991-04-23 Mag-Tek, Inc. Composite ticket processing unit
US5051565A (en) * 1990-02-26 1991-09-24 Johnson Service Company Baggage and passenger matching method and system
US5121407A (en) * 1990-09-27 1992-06-09 Pittway Corporation Spread spectrum communications system
US5151692A (en) * 1987-12-11 1992-09-29 Omron Tateisi Electronics Co. Boarding gate seat checkin apparatus and method
US5317309A (en) * 1990-11-06 1994-05-31 Westinghouse Electric Corp. Dual mode electronic identification system
US5365551A (en) * 1992-12-15 1994-11-15 Micron Technology, Inc. Data communication transceiver using identification protocol
US5401944A (en) * 1990-11-20 1995-03-28 Symbol Technologies, Inc. Traveler security and luggage control system
US5406263A (en) * 1992-07-27 1995-04-11 Micron Communications, Inc. Anti-theft method for detecting the unauthorized opening of containers and baggage
US5432027A (en) * 1994-03-02 1995-07-11 Micron Communications, Inc. Button-type battery having bendable construction, and angled button-type battery
US5455851A (en) * 1993-07-02 1995-10-03 Executone Information Systems, Inc. System for identifying object locations
US5494495A (en) * 1994-10-11 1996-02-27 Micron Communications, Inc. Method of forming button-type batteries
US5497140A (en) * 1992-08-12 1996-03-05 Micron Technology, Inc. Electrically powered postage stamp or mailing or shipping label operative with radio frequency (RF) communication
US5539775A (en) * 1993-03-17 1996-07-23 Micron Technology, Inc. Modulated spread spectrum in RF identification systems method
US5568512A (en) * 1994-07-27 1996-10-22 Micron Communications, Inc. Communication system having transmitter frequency control
US5594786A (en) * 1990-07-27 1997-01-14 Executone Information Systems, Inc. Patient care and communication system
US5621412A (en) * 1994-04-26 1997-04-15 Texas Instruments Incorporated Multi-stage transponder wake-up, method and structure
US5649296A (en) * 1995-06-19 1997-07-15 Lucent Technologies Inc. Full duplex modulated backscatter system
US5652570A (en) * 1994-05-19 1997-07-29 Lepkofker; Robert Individual location system
US5661799A (en) * 1994-02-18 1997-08-26 Infosafe Systems, Inc. Apparatus and storage medium for decrypting information
US5790946A (en) * 1993-07-15 1998-08-04 Rotzoll; Robert R. Wake up device for a communications system
US5809142A (en) * 1996-08-14 1998-09-15 Texas Instruments Incorporated Method and system for calculating a user account balance in a recognition system
US5842118A (en) * 1996-12-18 1998-11-24 Micron Communications, Inc. Communication system including diversity antenna queuing
US5914671A (en) * 1997-02-27 1999-06-22 Micron Communications, Inc. System and method for locating individuals and equipment, airline reservation system, communication system
US5942987A (en) * 1994-09-09 1999-08-24 Intermec Ip Corp. Radio frequency identification system with write broadcast capability
US5952922A (en) * 1996-12-31 1999-09-14 Lucent Technologies Inc. In-building modulated backscatter system
US5988510A (en) * 1997-02-13 1999-11-23 Micron Communications, Inc. Tamper resistant smart card and method of protecting data in a smart card
US6021326A (en) * 1996-11-04 2000-02-01 Uniden America Corporation Trunked multi-site dispatch network for trunking radios
US6034622A (en) * 1995-08-18 2000-03-07 Robert A. Levine Location monitoring via implanted radio transmitter
US6130302A (en) * 1996-08-19 2000-10-10 Northwestern University Synthesis and use of (polyfluoroaryl)fluoroanions of aluminum, gallium and indium

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US515692A (en) * 1894-02-27 Car-brake
US3719943A (en) * 1971-02-18 1973-03-06 Aradar Corp Selective identity system
US5408515A (en) * 1988-04-29 1995-04-18 Mobile Telecommunication Technologies Ground-to-air telephone calling system and related method for directing a call to a particular passenger
FR2673743A1 (en) * 1991-03-04 1992-09-11 Ragagnin Moreno Process and device for monitoring the presence of individuals within premises
JPH04313181A (en) 1991-03-25 1992-11-05 Mitsubishi Electric Corp Automatic ticket checking and collecting machine and automatic ticket vending machine
GR1001326B (en) * 1991-07-18 1993-08-31 Panagiotis Anagnostopoulos Method for personal communication information guidance and fast dispatch of procedures at airports
DE4319878A1 (en) * 1992-06-17 1993-12-23 Micron Technology Inc High frequency identification system card - has integrated circuit chip or carrier layer sealed by top layer and coupled to batteries and antenna system
JPH07210713A (en) 1994-01-10 1995-08-11 Nippon Signal Co Ltd:The Automatic ticket examining machine
US5812617A (en) * 1994-12-28 1998-09-22 Silcom Research Limited Synchronization and battery saving technique
US6130602A (en) 1996-05-13 2000-10-10 Micron Technology, Inc. Radio frequency data communications device
US6034603A (en) * 1997-01-24 2000-03-07 Axcess, Inc. Radio tag system and method with improved tag interference avoidance
CA2468087C (en) 2001-11-21 2013-06-25 General Instrument Corporation Macroblock level adaptive frame/field coding for digital video content

Patent Citations (42)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3750103A (en) * 1970-12-30 1973-07-31 Gen Computing Equipment Corp Electronic system employing plural processing stations for issuing airline boarding passes while effecting seat assignments, and generally for parcelling elements of an ordered set
US4075632A (en) * 1974-08-27 1978-02-21 The United States Of America As Represented By The United States Department Of Energy Interrogation, and detection system
US4247759A (en) * 1978-10-10 1981-01-27 Cubic Western Data Self-service passenger ticketing system
US4449186A (en) * 1981-10-15 1984-05-15 Cubic Western Data Touch panel passenger self-ticketing system
US4471345A (en) * 1982-03-05 1984-09-11 Sensormatic Electronics Corporation Randomized tag to portal communication system
US4926182A (en) * 1986-05-30 1990-05-15 Sharp Kabushiki Kaisha Microwave data transmission apparatus
US4984156A (en) * 1986-12-05 1991-01-08 Omron Tateisi Electronics Co. Automatic checkin apparatus
US4931932A (en) * 1987-09-28 1990-06-05 Travelsoft, Inc. Computerized system with means to automatically clear and sell wait-listed customer reservations
US5151692A (en) * 1987-12-11 1992-09-29 Omron Tateisi Electronics Co. Boarding gate seat checkin apparatus and method
US5010240A (en) * 1989-04-11 1991-04-23 Mag-Tek, Inc. Composite ticket processing unit
US5051565A (en) * 1990-02-26 1991-09-24 Johnson Service Company Baggage and passenger matching method and system
US5689229A (en) * 1990-07-27 1997-11-18 Executone Information Systems Inc. Patient care and communication system
US5594786A (en) * 1990-07-27 1997-01-14 Executone Information Systems, Inc. Patient care and communication system
US5121407A (en) * 1990-09-27 1992-06-09 Pittway Corporation Spread spectrum communications system
US5317309A (en) * 1990-11-06 1994-05-31 Westinghouse Electric Corp. Dual mode electronic identification system
US5401944A (en) * 1990-11-20 1995-03-28 Symbol Technologies, Inc. Traveler security and luggage control system
US5406263A (en) * 1992-07-27 1995-04-11 Micron Communications, Inc. Anti-theft method for detecting the unauthorized opening of containers and baggage
US5497140A (en) * 1992-08-12 1996-03-05 Micron Technology, Inc. Electrically powered postage stamp or mailing or shipping label operative with radio frequency (RF) communication
US5365551A (en) * 1992-12-15 1994-11-15 Micron Technology, Inc. Data communication transceiver using identification protocol
US5539775A (en) * 1993-03-17 1996-07-23 Micron Technology, Inc. Modulated spread spectrum in RF identification systems method
US5455851A (en) * 1993-07-02 1995-10-03 Executone Information Systems, Inc. System for identifying object locations
US5790946A (en) * 1993-07-15 1998-08-04 Rotzoll; Robert R. Wake up device for a communications system
US5661799A (en) * 1994-02-18 1997-08-26 Infosafe Systems, Inc. Apparatus and storage medium for decrypting information
US5432027A (en) * 1994-03-02 1995-07-11 Micron Communications, Inc. Button-type battery having bendable construction, and angled button-type battery
US5621412A (en) * 1994-04-26 1997-04-15 Texas Instruments Incorporated Multi-stage transponder wake-up, method and structure
US5652570A (en) * 1994-05-19 1997-07-29 Lepkofker; Robert Individual location system
US5568512A (en) * 1994-07-27 1996-10-22 Micron Communications, Inc. Communication system having transmitter frequency control
US5942987A (en) * 1994-09-09 1999-08-24 Intermec Ip Corp. Radio frequency identification system with write broadcast capability
US5494495A (en) * 1994-10-11 1996-02-27 Micron Communications, Inc. Method of forming button-type batteries
US5649296A (en) * 1995-06-19 1997-07-15 Lucent Technologies Inc. Full duplex modulated backscatter system
US6034622A (en) * 1995-08-18 2000-03-07 Robert A. Levine Location monitoring via implanted radio transmitter
US5809142A (en) * 1996-08-14 1998-09-15 Texas Instruments Incorporated Method and system for calculating a user account balance in a recognition system
US6130302A (en) * 1996-08-19 2000-10-10 Northwestern University Synthesis and use of (polyfluoroaryl)fluoroanions of aluminum, gallium and indium
US6021326A (en) * 1996-11-04 2000-02-01 Uniden America Corporation Trunked multi-site dispatch network for trunking radios
US5842118A (en) * 1996-12-18 1998-11-24 Micron Communications, Inc. Communication system including diversity antenna queuing
US5952922A (en) * 1996-12-31 1999-09-14 Lucent Technologies Inc. In-building modulated backscatter system
US5988510A (en) * 1997-02-13 1999-11-23 Micron Communications, Inc. Tamper resistant smart card and method of protecting data in a smart card
US5914671A (en) * 1997-02-27 1999-06-22 Micron Communications, Inc. System and method for locating individuals and equipment, airline reservation system, communication system
US6127917A (en) * 1997-02-27 2000-10-03 Micron Technology, Inc. System and method for locating individuals and equipment, airline reservation system, communication system
US6509829B1 (en) * 1997-02-27 2003-01-21 Micron Technology, Inc. System and method for locating individuals and equipment, airline reservation system, communication system
US20060061453A1 (en) * 1997-02-27 2006-03-23 Tuttle John R System and method for locating individuals and equipment, airline reservation system, communication system
US7030732B2 (en) * 1997-02-27 2006-04-18 Micron Technology, Inc. System and method for locating individuals and equipment, airline reservation system, communication system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060061453A1 (en) * 1997-02-27 2006-03-23 Tuttle John R System and method for locating individuals and equipment, airline reservation system, communication system
US20070290879A1 (en) * 1997-02-27 2007-12-20 Keystone Technology Solutions, Llc System and Method for Locating Individuals and Equipment, Airline Reservation System, Communication System
US20070290848A1 (en) * 1997-02-27 2007-12-20 Keystone Technology Solutions, Llc System and Method for Locating Individuals and Equipment, Airline Reservation System, Communication System
US7570151B2 (en) 1997-02-27 2009-08-04 Keystone Technology Solutions, Llc System and method for locating individuals and equipment, airline reservation system, communication system
US20090079565A1 (en) * 2007-09-26 2009-03-26 General Electric Company System and method for tracking an inventory within an asset
US7928844B2 (en) * 2007-09-26 2011-04-19 General Electric Company System and method for tracking an inventory within an asset
US20100013601A1 (en) * 2008-03-20 2010-01-21 Checkpoint Systems, Inc. Applique Nodes for Performance and Functionality Enhancement in Radio Frequency Identification Systems
US8217760B2 (en) * 2008-03-20 2012-07-10 Checkpoint Systems, Inc. Applique nodes for performance and functionality enhancement in radio frequency identification systems
US20120306651A1 (en) * 2011-06-01 2012-12-06 Jobsite Resources Llc Mobile perimeter access security system
US9123224B2 (en) * 2011-06-01 2015-09-01 Jobsite Resources, Llc Mobile perimeter access security system
US9659336B2 (en) 2012-04-10 2017-05-23 Bags, Inc. Mobile baggage dispatch system and method

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JP2000510985A (en) 2000-08-22
DE69813582D1 (en) 2003-05-22
WO1998038600A1 (en) 1998-09-03
US7030732B2 (en) 2006-04-18
CA2282376C (en) 2002-07-30
US20070290879A1 (en) 2007-12-20
US20070290848A1 (en) 2007-12-20
CA2282376A1 (en) 1998-09-03
AU6434798A (en) 1998-09-18
US20030122685A1 (en) 2003-07-03
US6127917A (en) 2000-10-03
US7570151B2 (en) 2009-08-04
DE69813582T2 (en) 2004-01-08
EP1012793A1 (en) 2000-06-28
ATE237851T1 (en) 2003-05-15
JP3277281B2 (en) 2002-04-22
US6509829B1 (en) 2003-01-21
US5914671A (en) 1999-06-22
EP1012793B1 (en) 2003-04-16
US20060061453A1 (en) 2006-03-23

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