Location position system for relay assisted tracking

• US 6,512,478 B1
• Filed: 02/26/2000
• Issued: 01/28/2003
• Est. Priority Date: 12/22/1999
• Status: Expired due to Term

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Rockwell Technologies, LLC (Teledyne Technologies Incorporated)
• Inventors: Chien, Charles
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/513,982
• Time in Patent Office: 1,067 Days
• Field of Search: 342/357.09, 342/357.1, 342/457, 342/385, 342/386, 701/207, 701/213, 340/572.1
• US Class Current: 342/357.25
• 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 5/0215 Interference
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• 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
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00
• CPC Class Codes: G08B 21/0269 System arrangements wherein the object is to detect the exact location of child or item using a navigation satellite system, e.g. GPS
• CPC Class Codes: G08B 25/009 Signalling of the alarm condition to a substation whose identity is signalled to a central station, e.g. relaying alarm signals in order to extend communication range

Abstract

An extensible short-range tracking system is disclosed. The tracking system disclosed is a multi-level tracking system. At the first level is an RF tag, which is a transmit-only unit that transmits information including minimally an identification number. The transmission from the RF tags are sporadic with timing depending upon the application at implementation. Generally, the transmission timing comprises a transmission, which is repeated periodically at random times. Transmissions from the RF tags are received in a series of relays. The relays may calculate the position of the tags by knowing the position of the relays and the time difference of arrival of the signals from the RF tags by several relays or may pass the information needed to calculate position to a base station. Alternately, the RF tags may generate position information and transmit that information along with the RF tag identifier to the relays. The relays, which may be networked among themselves, then relay the information from the tags to a base station unit. The base station unit may be part of various applications such as a fire control system in a military application or an inventory system in an industrial application.

Claims

1. A system for tagging and locating objects passing through a general area comprising:

a plurality of tags transmitting signals containing a tag identifier;

a dispenser for deploying the plurality of tags to a corresponding plurality of locations over the general area, the deployed tags being in locations within the general area such that at least one of the tags is likely to contact and become attached to at least one object upon the at least one object passing through the general area;

a relay for accepting tag transmissions from the plurality of tags, processing information contained in the tag transmissions within a computing element and for transmitting information related to the tags; and

a base station for receiving a transmission from at least one relay and for providing object location information from the transmission.

2. A system as in claim 1 wherein the tags commence transmitting signals containing a tag identifier upon receipt of a trigger signal.

3. A system as in claim 2 wherein the dispenser, which dispenses the tags, also provides the trigger signal.

4. A system as in claim 1 wherein the tags transmitting signals transmit spread spectrum signals.

5. A system as in claim 1 wherein the tags transmitting signals transmit the signals at pseudo-random intervals.

6. A system as in claim 1 wherein the relay further comprises a precision time element for determining the time of arrival of the signals transmitted from the tags in order to determine the location of the tags.

7. A system as in claim 6 wherein the precision time element comprises a Global Positioning System receiver.

8. A system as in claim 1 wherein the relay further comprises:

a receiver for receiving transmissions containing information, related to the tags, from at least one further relay; and

a transmitter for transmitting information, related to the tags, to at least one further relay.

9. A system as in claim 1 wherein the relay employs a networking protocol within the computing element for receiving information from other relays and for aggregating information received from the plurality of tags with information received from other relays.

10. A system as in claim 1 wherein the networking protocol routes the information received from the plurality of tags and other relays.

11. A system as in claim 9 wherein the networking protocol within the computing element further disseminates the aggregated information to other relays.

12. A system as in claim 9 wherein the networking protocol within the computing element coordinates processes for determining time delay of arrival for the information received from the plurality of tags and the other relays.

13. A system as in claim 1 wherein the dispenser deploys the plurality of tags in a corresponding plurality of pseudo-random locations.

14. A system as in claim 1 wherein the base station is mobile.

15. A system as in claim 1 wherein the dispenser deploys the plurality of tags utilizing an explosive charge.

16. A system as in claim 1 wherein the dispenser deploys the plurality of tags utilizing a pneumatic impulse.

17. A system as in claim 1 wherein the relay is located at a pseudo-random location.

18. A system as in claim 1 wherein the dispenser deploys the plurality of tags in specific locations within the general area.

19. A system as in claim 1 wherein the plurality of tags resemble natural objects.

20. A system as in claim 1 wherein the base station controls an automated weapon guidance system for guiding weapons toward the object location.

21. A system as in claim 1 wherein the base station tracks the location of inventory.

22. A system as in claim 1 wherein the base station tracks the location of packages.

23. A system as in claim 1 wherein the dispenser deploys the plurality of tags upon activation by a proximity sensor.

24. A system as in claim 1 wherein the plurality of tags become affixed to proximate objects by means of at least one of an adhesive material, attaching hook, and magnetized material.

25. A system as in claim 1 further comprising:

a plurality of relays for accepting the transmissions from the plurality of tags;

means for storing time of arrival of the transmissions at the plurality of relays;

means for receiving the time of arrival of the transmissions from the plurality of relays;

means for determining the position of at least one relay; and

means for determining the position of the tag by computing the time delay of arrival of the transmissions at the plurality of relays and the position of the at least one relay.

26. A system as in claim 25 wherein the means for determining the position of at least one relay comprises using a Global Positioning System to determine the position of the at least one relay.

27. A system as in claim 25 wherein the means for determining the position of at least one relay comprises means for manually programming the position into the at least one relay.

28. A system as in claim 25, further comprising:

means for decoding Global Positioning System data contained in the transmissions.

29. A system as in claim 25, further comprising:

means for providing Inertial Navigational System information from at least one tag; and

means for computing a position of the tag by calculating movement, using the Inertial Navigational System data, of the tag from an initial tag position.

30. An apparatus for transmitting a signal containing an identifier the apparatus comprising:

a power source for providing power to the apparatus;

a receiver for receiving a signal containing an initial position of the apparatus from a dispenser which dispenses the apparatus;

a computing unit programmed to determine a location of the apparatus;

an antenna; and

a transmitter coupled to the antenna for transmitting a signal containing an identifier and information corresponding to the determined location.

31. An apparatus as in claim 30 wherein the computing unit performs a power cycling of circuits not in use during the time the signal is not being transmitted.

32. An apparatus as in claim 30 wherein the power source comprises a battery and a switched capacitor, the switched capacitor for reducing the peak current drain of the battery.

33. An apparatus as in claim 30 wherein the power source comprises a power receiving circuit for receiving power in the form of radio frequency (RF) energy coupled into the power source.

34. An apparatus as in claim 30 wherein the transmitter is a spread spectrum transmitter.

35. An apparatus as in claim 30 wherein the computing unit is programmed to begin transmission upon the receipt of a trigger signal.

36. An apparatus as in claim 30 wherein the computing unit is programmed to begin asynchronous transmission upon the receipt of a trigger signal generated by the dispenser which dispenses the apparatus.

37. An apparatus as in claim 30 wherein the transmitter generates the transmit signal using a non crystal locked time base.

38. An apparatus as in claim 30 wherein the apparatus further comprises a Global Positioning System unit and transmits a signal derived from the Global Positioning System unit.

39. An apparatus as in claim 30 wherein the apparatus further comprises an Inertial System Navigation unit and transmits a signal derived from the Inertial Navigation System unit.

40. A system as in claim 31 wherein the information is routed to the base station.

41. A system as in claim 31 wherein the information is routed to other relays.

42. An apparatus as in claim 30 wherein the computing unit is further programmed to control the timing of the transmission of the signal.

43. A method for locating objects the method comprising:

providing a tag unit for transmitting a first signal containing identifying information, the tag unit comprising a computing unit which is programmed to accept positioning coordinates of the tag unit from a dispenser, which dispenses the tag unit;

receiving the first signal containing identifying information in a relay unit;

deriving, from the first signal, information concerning a location of the tag unit;

transmitting a further signal, from the relay unit, containing the derived information concerning the location of the tag unit;

receiving the further signal in a tag location determination unit; and

processing the further signal within the tag location determination unit to derive the location of the tag unit.

44. A method as in claim 43 wherein receiving and processing the further signal in a tag location determination unit comprises receiving and processing the further signal in a base station.

45. A method as in claim 43 wherein receiving and processing the further signal in a tag location determination unit comprises receiving and processing the further signal in another relay unit.

46. A method as in claim 43 wherein transmitting the first signal further comprises transmitting at pseudo-random intervals.

47. A method as in claim 43 wherein transmitting the first signal and the further signal further comprises transmitting using spread spectrum techniques.

48. A method as in claim 43 wherein deriving, from the first signal, information concerning the location of the tag unit further comprises using a Global Positioning System receiver to derive the location of the tag unit.

49. A method as in claim 43 wherein deriving, from the first signal, information concerning the location of the tag unit further comprises:

decoding Inertial Navigational System information from the first signal; and

computing the location by calculating the movement, using the Inertial Navigation System data, of the tag from a previous tag location.

50. A method as in claim 43 wherein deriving, from the first signal, information concerning the location of the tag unit further comprises decoding Global Positioning System data provided by the tag in the first signal.

51. A method as in claim 43 wherein processing the further signal within the base station unit to derive a location of the tag unit comprises computing the location of the tag unit using the time delay of arrival of the first signal at a plurality of relay units, and the locations of the relay units.

52. A method for propagating relay locations within an array of relays, comprising:

providing location information to each relay within a first group of relays within the array;

transmitting signals containing the location information from each relay within the first group of relays to each relay within a second group of relays within the array; and

determining a location of each relay within the second group of relays based on the location information received from each relay within the first group of relays;

wherein each relay within the second group of relays determines its own location.

53. The method recited in claim 52 wherein determining a location of each relay within the second group of relays comprises determining a time of arrival of the signals at each relay within the second group of relays and computing a time delay of arrival of the signals.

54. The method recited in claim 52, further comprising:

transmitting signals containing location information from each relay within the second group of relays to each relay within a third group of relays within the array; and

determining a location of each relay within the third group of relays based on the location information received from each relay within the second group of relays;

wherein each relay within the third group of relays determines its own location.

55. The method recited in claim 52, wherein providing location information to each relay within a first group of relays within the array comprises providing Global Positioning System units within each relay within the first group.

56. The method recited in claim 53, further comprising using topographical information in combination with the computed time delay of arrival of the signals from the first group of relays to determine the location of each relay within the second group of relays.

57. A method for propagating relay locations within an array of relays, comprising:

providing location information to each tag within a group of tags;

transmitting signals containing the location information from each tag within the group of tags to each relay within a group of relays within the array; and

determining a location of each relay within the group of relays based on the location information received from each tag within the group of tags;

wherein each relay within the group of relays determines its own location.

58. The method recited in claim 57 wherein determining a location of each relay within the group of relays comprises determining a time of arrival of the signals at each relay within the group of relays and computing a time delay of arrival of the signals.