Enchanced time difference localization system

• US 6,108,555 A
• Filed: 12/26/1996
• Issued: 08/22/2000
• Est. Priority Date: 05/17/1996
• Status: Expired due to Term

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: KSI Inc. (Liberty Broadband Corp.)
• Inventors: Hinkle, Charles J. Jr., Maloney, John E., Stevenson, James O.
• Primary Examiner(s): LE, THANH C
• Application Number:
  US08/772,871
• Time in Patent Office: 1,335 Days
• Field of Search: 455/422, 455/424, 455/456, 455/457, 455/502, 455/503, 455/67.1, 455/67.2, 455/186.1, 340/988, 340/990, 340/991, 340/992, 340/993, 340/994, 342/356, 342/357, 342/450, 342/454, 342/457, 301/207
• US Class Current: 455/456.2
• CPC Class Codes: G01S 2205/006 for emergency situations
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and apparatus for locating a mobile radio communications transceiver in a cellular-telephone or cellular-like communications system use a simplified system for passive monitoring of the signals emitted by the transceiver. Two receiving base stations can determine the timing of signal arrivals from the remote transceiver. This timing information is then combined with collateral, position-sensitive information to determine the likely location of the transceiver. The present invention has particular applicability to roadway transportation in that it facilitates enhanced emergency services and roadside assistance in response to calls for assistance, and it permits the passive monitoring of traffic flow.

Claims

1. An apparatus for locating a mobile radio communications transceiver in an operating environment served by a wireless communications system, comprising:

two sensor stations of known location that receive a radio, signal form the mobile transceiver, each sensor station having at inter-site synchronization mechanism for common time standard maintenance, and each sensor station further having a corresponding signal characterization processing unit that determines from the radio signal, time of signal arrival information;

a source of collateral information related to a location of the mobile transceiver;

a processing unit that determines time difference of signal arrival information based on the time of signal arrival information determined by each said signal characterization processing unit; and

a processing unit that determines a probable position of the mobile transceiver based on the time difference of signal arrival information and the collateral information.

2. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 1, wherein the collateral information comprises databased information.

3. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 2, wherein the databased information comprises signal propagation characteristics of the operating environment of the mobile transceiver.

4. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 2, wherein the databased information comprises traffic flow characteristics.

5. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 4, wherein the traffic flow characteristics comprise speed distribution information.

6. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 2, wherein the databased information comprises localized event information.

7. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 2, wherein the databased information comprises descriptions of users of the wireless communication system.

8. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 2, wherein the databased information comprises topological information.

9. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 8, wherein the topological information comprises map information.

10. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 8, wherein the topological information comprises roadway configuration information.

11. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 10, wherein the roadway configuration information comprises speed limit information.

12. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 8, wherein the topological information comprises information concerning landmarks.

13. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 1, wherein the collateral information comprises communicated information.

14. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 13, wherein the communicated information comprises input from an operator.

15. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 13, wherein the communicated information comprises information on traffic conditions.

16. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 13, wherein the communicated information comprises road identification information.

17. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 1, wherein the collateral information comprises signal strength.

18. An apparatus for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 1, wherein the collateral information comprises two way signal travel time.

19. An apparatus for locating a mobile radio communications transceiver as claimed in claim 1, wherein the inter-site synchronization mechanism comprises a GPS receiver or a rubidium timing mechanism.

20. The apparatus of claim 1, wherein the time difference of arrival information is determined based on only the time of arrival information determined by each said signal characterization processing unit.

21. The apparatus of claim 20, wherein the probable position is determined based on only said time difference of arrival information and said collateral information.

22. The apparatus of claim 1, wherein the probable position is determined based only on said time difference of arrival information and said collateral information.

27. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 2, wherein the traffic flow characteristics comprise speed distribution information.

23. A method for locating a mobile radio communications transceiver in a wireless communications system that includes two sensor stations of substantially known location, comprising:

receiving, at the two sensor stations, a radio signal from the mobile transceiver;

determining time of signal arrival information based on said radio signal received at the two sensor stations;

determining time difference of signal arrival information based on said time of signal arrival information;

accessing collateral information related to a location of the mobile transceiver; and

determining a probable position of the mobile transceiver based on said time difference of signal arrival information and the collateral information.

24. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 23, wherein the collateral information comprises databased information.

25. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 24, wherein the databased information comprises signal propagation characteristics of the operating environment of the mobile transceiver.

26. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 24, wherein the databased information comprises traffic flow characteristics.

28. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 24, wherein the databased information comprises localized event information.

29. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 24, wherein the databased information comprises descriptions of users of the wireless communication system.

30. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 24, wherein the databased information comprises inputting topological information.

31. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 30, wherein the topological information comprises map information.

32. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 30, wherein the topological information comprises roadway configuration information.

33. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 30, wherein the topological information comprises speed limit information.

34. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 30, wherein the topological information comprises information concerning landmarks.

35. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 23, wherein the collateral information comprises communicated information.

36. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 35, wherein the communicated information comprises input from an operator.

37. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 35, wherein the communicated information comprises information on traffic conditions.

38. A method for locating a mobile radio communications transceiver in a cellular communications system as claimed in claim 23, wherein the collateral information comprises signal strength information.

39. A method for locating a mobile radio communication transceiver in a cellular communications system as claimed in claim 25, wherein the collateral information comprises two way signal travel time.

40. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 23, wherein the collateral information comprises information supplied by the wireless communication system.

41. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 40, wherein the information supplied by the wireless communication system comprises signal strength information.

42. A method for locating a mobile radio communications transceiver in a wireless communications system as claimed in claim 23, further comprising determining a plurality of time difference of signal arrival formation from the two sensor stations and determining a relative motion of a plurality of time difference of arrival hyperbola from the plurality of time difference of signal arrival information.

43. The method of claim 23, wherein said step of determining said time difference of arrival information comprises determining said time difference of arrival information based only on said time of arrival information determined by each said signal characterization processing unit.

44. The method of claim 43, wherein said step of determining said probable position comprises determining said probable location based only on said time difference of arrival information and said collateral information.

45. The method of claim 23, wherein said step of determining said probable position comprises determining said probable location based only on said time difference of arrival information and said collateral information.

46. A method for locating a mobile transceiver in a wireless communications system that includes a fist and second sensor station, the method comprising the steps of:

(a) receiving a radio signal at each of the first and second sensor stations;

(b) determining first time of signal arrival information corresponding to when the radio signal is received at the first sensor station;

(c) determining second time of signal arrival information corresponding to when the radio signal is received at the second sensor station;

(d) determining time difference of arrival information based on said first time of signal arrival information and said second time of signal arrival information;

(e) accessing collateral information relating to a location of the mobile transceiver; and

(f) determining a probable location of the mobile transceiver based on said time difference of arrival information and said collateral information.

47. The method of claim 46, wherein step (d) further comprises the step of determining a first set of time difference of arrival loci based on said time difference of arrival information.

48. The method of claim 47, wherein step (f) comprises determining said probable position based on said first set of time difference of arrival loci and said collateral information.

49. The method of claim 48, wherein said collateral information comprises roadway configuration information which includes speed limit information.

50. The method of claim 49, wherein step (d) further comprises the step of determining a second set of time difference of arrival loci by repeating steps (a) through (c) using the same first and second sensor stations.

51. The method of claim 50, wherein step (f) further comprises:

determining a velocity set for the mobile transceiver based on said first set of time difference of arrival loci and said second set of time difference of arrival loci; and

determining said probable position based on said velocity set for the mobile transceiver and said roadway configuration information.

52. The method of claim 50, wherein step (f) further comprises:

determining a direction of travel of the mobile transceiver based on said first time difference of arrival loci and said second time difference of arrival loci.

53. The method of claim 46, wherein step (e) comprises receiving said collateral information from an information provider.

54. The method of claim 46, wherein step (e) comprises determining said collateral information by measuring a signal strength of the radio signal, wherein said collateral information comprises said measured signal strength.

55. The method of claim 46, wherein step (e) comprises retrieving said collateral information from a database.

56. The method of claim 46, wherein said collateral information comprises at least one of signal propagation characteristics of the operating environment of the mobile transceiver, traffic flow characteristics, a description of users of the wireless communication system, topological information, standard route information, map information and communicated information.

57. The method of claim 46, wherein each of the sensor stations includes an inter-site synchronization mechanism for common time standard maintenance.

58. The method of claim 46, wherein said time difference of signal arrival information is determined based on only said first time of signal arrival information and said second time of signal arrival information.

59. The method of claim 58, wherein said probable position is determined based on only said time difference of signal arrival information and said collateral information.

60. The method of claim 46, wherein said probable position is determined based only on said time difference of signal arrival information and said collateral information.

61. An apparatus for locating a mobile transceiver in a wireless communications system that includes a first and second sensor station each having an inter-site synchronization mechanism for common time standard maintenance, comprising:

means for receiving a radio signal at each of the first and second sensor stations;

means for determining first time of signal arrival information corresponding to when the radio signal is received at the first sensor station;

means for determining second time of signal arrival information corresponding to when the radio signal is received at the second sensor station;

means for determining time difference of arrival information based on said first time of signal arrival information and said second time of signal arrival information;

means for accessing collateral information relating to a location of the mobile transceiver; and

means for determining a probable location of the mobile transceiver based on said time difference of arrival information and said collateral information.

62. A system for locating a mobile transceiver comprising:

a first sensor station that receives a radio signal transmitted by the mobile transceiver, said first sensor station having a corresponding first signal characterization processing unit that determines first time of signal arrival information based on said radii signal transmitted by the mobile transceiver;

a second sensor station tat receives said radio signal transmitted by the mobile transceiver, said second sensor station having a corresponding second signal characterization processing unit that determines second time of signal arrival information based on said radio signal transmitted by the mobile transceiver;

a processing unit, in communications with said first and second sensor stations, that determines time difference of signal arrival information based on said first time of signal arrival information and said second time of signal arrival information; and

a processing unit that determines a probable location of the mobile transceiver based on said time difference of signal arrival information and collateral information relating to a location of the mobile transceiver.

63. The system of claim 62, wherein said processing unit receives laid collateral information from an information provider.

64. The system of claim 62, wherein at least one, of said first and second signal characterization processing units determines said collateral information by measuring a signal strength of said radio signal, wherein said collateral information comprises said measured signal strength.

65. The system of claim 62, wherein said processing unit retrieves said collateral information from a database.

66. The system of claim 62, wherein each of the first and second sensor stations include an inter-site synchronization mechanism for common time standard maintenance.

67. The system of claim 62, wherein said time difference of signal arrival information is determined based on only said first time of signal arrival information and said second time of signal arrival information.

68. The system of claim 67, wherein said probable position is determined based on only said time difference of signal arrival information and said collateral information.

69. The system of claim 62, wherein said probable position is determined based only on said time difference of signal arrival information and said collateral information.

70. An apparatus for locating a mobile radio communications transceiver in an operating environment served by a wireless communications system, comprising:

two sensor stations of known location that receive a radio signal from the mobile transceiver;

a source of collateral information related to a location of the mobile transceiver;

a processing unit that determines time difference of signal arrival information based on said radio signal received at the two sensor stations; and

a processing unit that determines a probable position of the mobile transceiver based on said time difference of signal arrival information and said collateral information.

71. A method for locating a mobile transceiver in a wireless communications system that includes a first and second sensor station having known locations, the method comprising the steps of

receiving, at the first and second sensor stations, a radio signal from the mobile transceiver;

accessing collateral information related to a location of the mobile transceiver; and

determining time difference of signal arrival information based on said radio signal received at the first and second stations;

determining a probable position of the mobile transceiver based on said time difference of signal arrival information and said collateral information.