System and method for monitoring objects, people, animals or places

• US 7,479,884 B1
• Filed: 08/30/2005
• Issued: 01/20/2009
• Est. Priority Date: 08/31/2004
• Status: Expired due to Fees

• Current Assignee: Cedar Ridge Research LLC
• Original Assignee: Cedar Ridge Research LLC
• Inventors: Fullerton, Larry W.
• Primary Examiner(s): Bugg; George A
• Assistant Examiner(s): LAU, HOI CHING
• Application Number:
  US11/215,490
• Time in Patent Office: 1,239 Days
• Field of Search: 3405721-5729, 340/10.1, 342/51, 342/42, 342/44, 342/43, 342/109, 342/113, 342/118, 342/125, 342/128, 342/146
• US Class Current: 340/572.7
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/18 wherein range gates are used
• CPC Class Codes: G01S 13/756 using a signal generator for modifying the reflectivity of the reflector G01S13/758 takes precedence
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 7/024 using polarisation effects in waveguides H01P1/165; for aerials H01Q, e.g. H01Q15/22, H01Q15/24, H01Q19/195
• CPC Class Codes: G06K 19/067 Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management

Abstract

An improved system and method for monitoring objects, people, animals, or places uses a passive Modulating Reflector (MR) tag where an antenna is alternately short and open circuited according to a time-varying pattern by a modulating network thereby causing the reflective characteristics of the antenna to vary in accordance with the time-varying pattern. When an interrogator transmits an RF waveform that impinges on the antenna, the return signal reflecting off the antenna is modulated in accordance with the time-varying pattern allowing a remote receiver to demodulate information from the modulated return signal. The MR tag can be used with a wide variety of tag-interrogator configurations employing monostatic and/or bistatic radar techniques to allow monitoring, locating, and/or tracking of objects, people, animals, or place with which MR tags are associated.

Claims

1. A method for monitoring a person, animal, object, or place, comprising:

associating a modulating reflector tag with said person, animal, object, or place, said modulating reflector tag including an antenna structure having at least one characteristic modified in accordance with a pattern, said pattern intended to convey information pertaining to said person, animal, object, or place, said modulating reflector tag being located at a first location, said antenna structure employing retro reflector effects to improve signal-to-noise of said modulating reflector tag to enable an increased interrogation range;

transmitting an interrogation signal towards said modulating reflector tag using an interrogator located at a second location different from said first location, said interrogation signal reflecting off said modulating reflector tag as a return signal, said retro reflector effects causing said return signal to return directly back towards said interrogator regardless of where said interrogator is located relative to said modulating reflector tag;

receiving said return signal, said receiving occurring at said second location;

demodulating said received return signal to determine said information; and

monitoring said person, animal, object, or place based upon said demodulated information.

2. The method of claim 1, further comprising:

determining a range between said first location and said second location.

3. The method of claim 1, further comprising:

determining said first location.

4. The method of claim 3, wherein said first location is determined using at least one of a plurality of transmitting locations or a plurality of receiving locations.

5. The method of claim 3, wherein said person comprises one of:

an emergency responder;

military personnel;

a firefighter;

an employee;

a soldier;

a prisoner;

a swat team member;

a survivor; and

a friend.

6. The method of claim 1, wherein said animal comprises one of:

a pet;

a farm animal.

7. The method of claim 1, wherein said object comprises one of:

a vehicle;

inventory;

cargo;

a train;

a ship;

a semi trailer;

an aircraft;

a plane;

a helicopter;

an unmanned air vehicle;

an unmanned ground vehicle;

a weapon;

a tank;

a rocket launcher;

equipment;

a black box;

a land mine;

instrumentation for virtual gaming;

instrumentation for intra-body monitoring;

a sensor;

a life raft; and

a life preserver.

8. The method of claim 1, wherein said place comprises one of:

a location within a shipyard;

a location within an airport;

a location within a railroad yard;

a location within a manufacturing facility; and

a location within a storage facility.

9. The method of claim 1, further comprising:

associating said modulating reflector tag with a sensor.

10. The method of claim 1, further comprising:

using said information pertaining to said person, animal, object, or place for at least one of;

situational awareness;

identification of friend versus foe; and

command and control purposes.

11. A system for monitoring a person, animal, object, or place, comprising:

a modulating reflector tag at a first location, said modulating reflector tag being associated with said person, animal, object, or place, said modulating reflector tag including an antenna structure having at least one characteristic modified in accordance with a pattern, said pattern intended to convey information pertaining to said person, animal, object, or place, said antenna structure employing retro reflector effects to improve signal-to-noise of said modulating reflector tag to enable an increased interrogation range;

a transmitter at a second location that transmits an interrogation signal towards said modulating reflector tag, said interrogation signal reflecting off said modulating reflector tag as a return signal, said retro reflector effects causing said return signal to return directly back towards said second location regardless of where said transmitter is located relative to said modulating reflector tag; and

a receiver at said second location that receives and demodulates said received return signal to determine said information, wherein said information can be used to monitor said person, animal, object, or place.

12. The system of claim 11, wherein said transmitter and receiver function as a monostatic radar.

13. The system of claim 11, further comprising:

one or more additional receivers that receive one or more other return signals based upon one or more other interrogation signals.

14. The system of claim 13, wherein the position of said person, animal, object, or place is determined.

15. The system of claim 11, further comprising:

one or more additional transmitters that transmit one or more additional interrogation signals.

16. The system of claim 15, wherein said receiver determines a position of said person, animal, object or place.

17. A modulating reflector tag, comprising:

an antenna structure, said antenna structure employing retro reflector effects to improve signal-to-noise of said modulating reflector tag to enable an increased interrogation range, said retro reflector effects returning a return signal directly back towards an interrogator regardless of where said interrogator is located relative to said modulating reflector tag; and

a modulating network, said modulating network modifying at least one characteristic of said antenna structure in accordance with a pattern, said pattern intended to convey information pertaining to a person, animal, object, or place.