System and method for communicating with dormant radio frequency identification tags

• US 6,693,511 B1
• Filed: 09/24/1999
• Issued: 02/17/2004
• Est. Priority Date: 09/24/1999
• Status: Expired due to Term

• Current Assignee: GE Security Incorporated (Carrier Global Corporation)
• Original Assignee: GE Interlogix Incorporated (General Electric Company)
• Inventors: Seal, James
• Primary Examiner(s): Bangachon, William
• Application Number:
  US09/405,364
• Time in Patent Office: 1,607 Days
• Field of Search: 340/10.1, 340/10.2, 340/10.42, 340/10.6, 340/572.1, 340/572.4, 340/571, 340/5.8, 340/568.1, 340/2, 340/573.4, 340/539, 340/825.49, 455/82, 455/502, 455/343, 342/51, 342/50, 342/42, 342/44, 342/442, 342/357.07, 375/317, 380/28, 235/492
• US Class Current: 340/10.1
• CPC Class Codes: G01S 13/751 wherein the responder or reflector radiates a coded signal
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308

Abstract

The position of a radio frequency identification (RFID) transponder may be determined with respect to a plurality of stationary sensors located in an array within certain physical areas. Each sensor comprises a plurality of antenna coils arranged in unique physical orientations and capable of transmitting radio frequency signals of differing phase. The RFID transponder includes an antenna which receives the plurality of signals generated by the antenna coils, and compares the phase of at least two of the signals to determine the relative position of the transponder. The location of the transponder with respect to two or more sensor(s) may also be determined through measurement of the intensity of the signals received by the antenna coil of the transponder. The system and method may also transmit data between a sensor and a dormant (motionless) RFID transponder using a hand-held high intensity RF probe.

Claims

1. A method of transmitting data between a transceiver having a transmit coil and a dormant radio frequency identification (RFID) transponder having a receiving coil, the method comprising:

providing a transponder in a first state, said transponder comprising a sensor, wherein the sensor is operable to initiate generation of a wake up signal by said transponder placing said transponder in a second state;

generating a localized radio frequency signal having a first frequency and first intensity in proximity to said transponder using said transmit coil;

sensing said radio frequency signal at said first frequency with said receiving coil;

generating a wake up signal within said transponder when said first intensity of said radio frequency signal exceeds a predetermined value and said sensor initiates said generation of said wake up signal, said wake up signal removing said transponder from said first state and placing it in said second state; and

transmitting data between said transceiver and said transponder when said transponder is in said second state.

2. The method of claim 1, wherein the act of removing said transponder from a first state and placing it in a second state comprises removing said transponder from a dormant state, and placing it in an active state.

3. The method of claim 1, further comprising the act of transmitting an identification signal from said transceiver to said transponder which identifies said transceiver.

4. The method of claim 3, further comprising the act of authenticating said transceiver using said identification signal and data stored within said transponder.

5. The method of claim 1, wherein said first frequency is a discrete frequency.

6. The method of claim 1, wherein the act of generating the localized RF signal comprises generating a spread spectrum signal.

7. The method of claim 1, further comprising the act of measuring the time said intensity of said radio frequency signal exceeds said predetermined value, and deciding whether or not to remove said transponder from said first state based on said time exceeding a preset value.

8. The method of claim 1, wherein said transponder is placed in said second state by either an input from the sensor or said generation of said wake up signal.

9. The method of claim 1, wherein said transponder is placed in said second state by an input from the sensor concurrent with said generation of said wake up signal.

10. The method of claim 1, wherein said sensor is a motion sensor configured to place said transponder in said second state when said transponder is in motion.

11. The method of claim 1, wherein said sensor is a tamper detector configured to place said transponder in said second state when said transponder is tampered with.

12. The method of claim 1, wherein the sensor comprises a detector.

13. A system for communicating with a dormant radio frequency identification (RFID) tag having a directional antenna, the system comprising:

a transceiver capable of transmitting high intensity localized radio frequency signals, and receiving radio frequency signals transmitted by said RFID tag;

a signal generator capable of generating radio frequency signals of a predetermined intensity and spectral configuration for transmission by said transceiver;

a signal receiver capable of processing radio frequency signals received by said transceiver;

a detector capable of removing said RFID tag from said dormant state and placing said RFID tag in an active state, wherein said detector is configured to place said RFID tag in said active state when said RFID tag is tampered with and said high intensity localized radio frequency signals received by said RFID tag are above a predetermined level, and wherein in said active state said RFID tag may transmit and receive RF signals;

a processor, operatively coupled to said transceiver, signal generator, and receiver, said processor being capable of processing signals output from said receiver and obtaining data therefrom, and generating data for transmission to said dormant RFID tag via said transceiver;

a display operatively coupled to said processor;

an input device, operatively coupled to said processor, which receives inputs from a user; and

a power supply which supplies electrical power to said system;

wherein at least said transceiver is movably coupled to said system so that communication between said RFID tag and said system can occur regardless of orientation of said tag directional antenna.

14. The system of claim 13, wherein said input device comprises a touch screen integral with said display.

15. The system of claim 13, wherein said processor comprises a personal computer.

16. The system of claim 13, further comprising a storage device capable of storing said data.

17. The method of claim 13, wherein said sensor is a motion sensor configured to place said RFID tag in said active state when said transponder is in motion.

18. The system of claim 13, wherein said transceiver, said signal generator, said signal receiver, said display, and said input device are disposed in a handheld wand.

19. The method of claim 13, wherein said sensor is a tamper detector configured to place said RFID tag in said active state when said transponder is tampered with.

20. A communication system comprising a radio frequency identification tag wakeup circuit, the system comprising:

a transponder capable of receiving said radio frequency signal having data associated therewith;

at least one diode, operatively connected to said transponder, said at least one diode generating a wake up signal at its cathode when the intensity of said radio frequency signal exceeds a first predetermined value, wherein the transponder is configured to generate said wake up signal at said diode cathode; and

a diode limiter operatively coupled to said at least one diode which limits the voltage at said diode when said intensity exceeds a second predetermined value.

21. The method of claim 20, wherein said system further comprises a motion sensor configured to generate said wake up signal when said transponder is in motion.

22. The method of claim 20, wherein said system further comprises a tamper detector configured to generate said wake up signal when said transponder is tampered with.

23. A method of transmitting data between a transceiver having more than one transmit coil at fixed locations in a building and a dormant radio frequency identification (RFID) transponder having a receiving coil, the method comprising:

providing a transponder in a first state;

generating a localized radio frequency signal having a first frequency and first intensity in proximity to said transponder using said transmit coils;

sensing said radio frequency signal at said first frequency with said receiving coil;

generating a wake up signal within said transponder when said first intensity of said radio frequency signal exceeds a predetermined value, said wake up signal removing said transponder from said first state and placing it in said second state;

transmitting data between said transceiver and said transponder when said transponder is in said second state; and

determining a position of said transponder based on said radio frequency signal, wherein said determining is performed within said transponder.