METHOD AND APPARATUS FOR REAL-TIME LOCATION OF ASSETS

• US 20100295681A1
• Filed: 03/24/2010
• Published: 11/25/2010
• Est. Priority Date: 03/24/2009
• Status: Active Grant

• Current Assignee: Savi Technology Incorporated
• Original Assignee: Savi Technology Incorporated
• Inventors: Norair, John P., Burns, Patrick E.
• Granted Patent: US 8,390,442 B2
• Time in Patent Office: Days
• US Class Current: 340/572.1
• CPC Class Codes: G01S 11/06 using intensity measurements
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: Y10T 70/30 Hasp
• CPC Class Codes: Y10T 70/48 Arcuate locus
• CPC Class Codes: Y10T 70/5212 Sliding dead bolt

Abstract

A method and apparatus involve a plurality of first devices, and a second device movable relative thereto. According to one aspect, the first and second devices respectively transmit first information and second information containing unique identification codes, the first information also containing position information. The devices collectively include circuitry that estimates distances therebetween, one of the first and second information including the estimate. According to a different aspect, one of the second device and each first device transmits its identification code, and the devices collectively include circuitry that determines two successive sets of estimates representing respective distances between the second device and each first device. One of the second device and each first device transmits information that includes both estimates for that first device, and identification codes for the second device and that first device.

Claims

1. An apparatus comprising:

a first device that receives first wireless signals containing positioning information, and that transmits second wireless signals containing first information, said first information including an identification code uniquely identifying said first device, and said first information including position information based on said positioning information as recently received by said first device; and

a second device, one of said first and second device being movable relative to the other thereof, said second device transmitting third wireless signals containing second information, said second information including an identification code uniquely identifying said second device;

wherein said first and second devices collectively include ranging circuitry that determines an estimate of a distance between said first and second devices, one of said first information and said second information including said estimate as recently determined by said ranging circuitry.

2. An apparatus according to claim 1,

wherein said first device receives said third wireless signals;

wherein said ranging circuitry includes a signal strength evaluating section that is disposed in said first device and that determines a received strength of said third wireless signals; and

wherein said estimate is in said first information, and is said received strength as recently determined by said evaluating section.

3. An apparatus according to claim 2, wherein said second device receives said second wireless signals, and transmits fourth wireless signals containing third information, said third information including said identification code of said first device, said identification code of said second device, and position information based on said position information in said first information.

4. An apparatus according to claim 3, wherein said position information in said third information and said position information in said second first information each include said positioning information.

5. An apparatus according to claim 3, including a reader that receives said fourth wireless signals.

6. An apparatus according to claim 2, including a plurality of third devices, said second device being movable relative to said third devices, and each said third device:

receiving said first and third wireless signals;

having a signal strength evaluating section that determines a received strength of said third wireless signals, said received strength representing an estimate of a distance between said second device and that said third device; and

transmitting fourth wireless signals containing third information, said third information including an identification code uniquely identifying that said third device, said received strength as recently determined by said evaluating section in that said third device, and position information based on said positioning information from said first wireless signals as recently received by that said third device.

7. An apparatus according to claim 6, wherein said second device receives said second and fourth wireless signals, and transmits fifth wireless signals containing fourth information, said fourth information including said identification code of said second device, said identification code of said first device, said identification codes of each of said third devices, and further position information based on said position information in said first information and said position information in said third information from each said third device.

8. An apparatus according to claim 1,

wherein said second device receives said second wireless signals;

wherein said ranging circuitry includes a signal strength evaluating section that is disposed in said second device and that determines a received strength of said second wireless signals;

wherein said estimate is in said second information, and is said received strength as recently determined by said evaluating section; and

wherein said second information includes said identification code of said first device, and position information based on said position information in said first information.

9. An apparatus according to claim 8, wherein said position information in said second information and said position information in said first information each include said positioning information.

10. An apparatus according to claim 8, including a reader that receives said third wireless signals.

11. An apparatus according to claim 1, including a plurality of third devices, said second device being movable relative to said third devices, and each said third device:

receiving said first wireless signals; and

transmitting fourth wireless signals containing third information, said third information including an identification code uniquely identifying that said third device, and position information based on said positioning information from said first wireless signals as recently received by that said third device.

12. An apparatus according to claim 11,

wherein said second device receives said second wireless signals, and receives said fourth wireless signals from each said third device;

wherein said ranging circuitry includes a signal strength evaluating section that is disposed in said second device, that determines a received strength of said second wireless signals, and that determines a received strength of said fourth wireless signals from each said third device;

wherein said estimate is in said second information, and includes said received strength for said first wireless signals and said received strength for said fourth wireless signals from each said third device, as recently determined by said evaluating section; and

wherein said second information includes said identification code of said first device, said identification codes for each of said third devices, and position information based on said position information in said first information and said position information in said third information from each said third device.

13. An apparatus according to claim 1, wherein said position information in said first information includes said positioning information.

14. An apparatus according to claim 1,

wherein said first device transmits fourth wireless signals that include third information, said third information including said identification code of said first device;

wherein said second device receives said fourth wireless signals;

wherein said ranging circuitry includes a signal strength evaluating section that is disposed in said second device and that determines a received strength of said fourth wireless signals; and

wherein said estimate is in said second information, and is said received strength as recently determined by said evaluating section.

15. An apparatus according to claim 14, wherein said first device receives said third wireless signals, said first information including said identification code of said second device, and information based on said received strength from said second information.

16. An apparatus according to claim 14, including a reader that receives said second wireless signals.

17. An apparatus according to claim 14, including a plurality of third devices, said first device being movable relative to said third devices, and each said third device:

receiving said fourth wireless signals;

having a signal strength evaluating section determines a received strength of said fourth wireless signals; and

transmitting fifth wireless signals containing fourth information, said fourth information including an identification code uniquely identifying that said third device, and said received strength as recently determined by said evaluating section in that said third device.

18. An apparatus according to claim 17, wherein said first device receives said third wireless signals and said fifth wireless signals, said first information including said identification code of said second device, said identification code of each said third device, said received strength from said second information, and said received strength from said fourth information from each said third device.

19. An apparatus according to claim 17, including a carrier that has said first device supported thereon, and that moves along predetermined paths of travel in relation to said second and third devices.

20. An apparatus according to claim 1, wherein said first wireless signals are satellite signals.

21. An apparatus according to claim 20, wherein said first wireless signals are global positioning system (GPS) signals.

22. An apparatus according to claim 1, wherein said first device includes a sensor that senses an ambient condition in the region of said first device, said first information including a sensor reading recently obtained from said sensor.

23. An apparatus according to claim 22, wherein said ambient condition is one of an ambient temperature, an ambient humidity, an ambient pressure, an ambient moisture level, an ambient level of radiation, and an ambient concentration of a selected gas.

24. An apparatus according to claim 1, including a signpost that receives said first wireless signals, and that transmits wireless signpost signals that include position information based on said positioning information in said first wireless signals, and an identification code uniquely identifying said signpost.

25. An apparatus according to claim 24, wherein said signpost includes a sensor that senses an ambient condition in the vicinity of said signpost, said signpost signals further including a sensor reading recently obtained from said sensor.

26. An apparatus according to claim 25, wherein said ambient condition is one of an ambient temperature, an ambient humidity, an ambient pressure, an ambient moisture level, an ambient level of radiation, and an ambient concentration of a selected gas.

27. An apparatus comprising:

a plurality of first devices that are spaced from each other, that each have a transmitter section, and that each have a respective unique identification code; and

a second device that is movable relative to said first devices, that includes a transmitter section, and that has a unique identification code;

wherein one of said second device and each of said first devices transmits wireless signals containing said identification code thereof;

wherein said first and second devices collectively include ranging circuitry that determines at a first time a first set of estimates of the respective distances between said second device and each of said first devices, and that determines at a second time subsequent to said first time a second set of estimates of the respective distances between said second device and each of said first devices; and

wherein for each said first device, one of said second device and that said first device transmits wirelessly from said transmitter section thereof information that includes the identification code for said second device, the identification code for that said first device, said estimate from said first set corresponding to that said first device, and said estimate from said second set corresponding to that said first device.

28. An apparatus according to claim 27, including:

a reader having a receiver section that receives said information transmitted wirelessly; and

a direction determination section that is coupled to said reader, and that determines as a function of said information an approximate direction of movement of said second device between said first and second times.

29. An apparatus according to claim 27,

wherein said wireless signals are transmitted by said second device;

wherein each of said first devices includes a receiver section that receives said wireless signals; and

wherein said ranging circuitry includes in each of said first devices a ranging section that determines, for each of said first and second sets, said estimates for that said first device as a function of said wireless signals received by that said first device.

30. An apparatus according to claim 29, including an interrogator section that wirelessly transmits a first interrogation command at said first time and a second interrogation command at said second time, said second device being responsive to said first command for effecting a first transmission of said wireless signals to cause generation of said first set of estimates, and being responsive to said second command for effecting a second transmission of said wireless signals to cause generation of said second set of estimates.

31. An apparatus according to claim 29, wherein each said ranging section includes a signal strength evaluating section that determines a received strength of said wireless signals, each of said estimates in said first and second sets being a respective said received strength.

32. An apparatus according to claim 29, wherein said information for each said first device is wirelessly transmitted by that said first device.

33. An apparatus according to claim 29,

wherein each said first device transmits wireless signals that include the identification code for that said first device, said estimate from said first set for that said first device, and said estimate from said second set for that said first device;

wherein said second device includes a receiver section that receives said wireless signals from each of said first devices; and

wherein said information for each said first device is wirelessly transmitted by said second device.

34. An apparatus according to claim 27,

wherein said wireless signals are transmitted by said first devices;

wherein said second device includes a receiver section that receives said wireless signals from said first devices;

wherein said ranging circuitry includes in said second device a ranging section that determines said estimates for each of said first and second sets, said estimates being a function of said wireless signals received by said second device; and

wherein said information for each said first device is wirelessly transmitted by said second device.

35. An apparatus according to claim 34, including an interrogator section that wirelessly transmits a first interrogation command at said first time and a second interrogation command at said second time, said second device being responsive to said first command for generating said first set of estimates, and being responsive to said second command for generating said second set of estimates.

36. An apparatus according to claim 34, wherein said ranging section includes a signal strength evaluating section that determines a received strength of said wireless signals, each of said estimates in said first and second sets being a respective said received strength.

37. An apparatus according to claim 27, wherein said first devices are located near a chokepoint.

38. An apparatus according to claim 27, wherein one of said second device and each said first device:

includes circuitry that receives wireless signals containing positioning information; and

transmits wirelessly from said transmitter section thereof information that includes said positioning information.