Multiple pass location processor

• US 7,023,383 B2
• Filed: 08/11/2004
• Issued: 04/04/2006
• Est. Priority Date: 01/08/1999
• Status: Expired due to Term

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: TruePosition Incorporated
• Inventors: Anderson, Robert J., Ward, Matthew L., Stilp, Louis A.
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US10/915,786
• Publication Number:
  US 20050024265A1
• Time in Patent Office: 601 Days
• Field of Search: 342/357.01, 342/357.02, 342/451, 342/457, 342/463, 455/456, 455/457
• US Class Current: 342/457
• CPC Class Codes: G01S 1/026 of associated receivers
• CPC Class Codes: G01S 2205/06 Emergency
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

A multiple pass location processing method, for use in a wireless location system (WLS), comprises identifying a received transmission as requiring multiple pass location processing whereby the WLS produces a first, lower quality location estimate and then subsequently produces a second, higher quality location estimate. The WLS then produces the first location estimate and provides it to a first location application, and then produces the second location estimate. The second location estimate may be a more accurate estimate than the first location estimate and/or of a higher confidence than the first location estimate. This method is suitable, but not limited, for use in connection with locating a wireless transmitter involved in an emergency services call and routing the call to a call center.

Claims

1. A multiple pass location processing method for use in a wireless location system (WLS) capable of locating a wireless transmitter based on a transmission received from the wireless transmitter, comprising the steps of:

(a) producing a first, lower quality location estimate and providing said first location estimate to a first location application; and

(b) subsequently producing a second, higher quality location estimate for delivery to a second location application, wherein the second location application may be the same as the first location application or different from the first location application, and wherein the second location estimate is characterized as being either more accurate or of a higher confidence than the first location estimate.

2. A method as recited in claim 1, wherein the second location estimate is a more accurate estimate than the first location estimate.

3. A method as recited in claim 1, wherein the second location estimate is of a higher confidence than the first location estimate.

4. A method as recited in claim 1, further comprising identifying a plurality of received transmissions as requiring multiple pass location processing.

5. A method as recited in claim 1, further comprising identifying one or more wireless transmitters as requiring multiple pass location processing.

6. A method as recited in claim 1, wherein the received transmission is identified as requiring multiple pass location processing based on the identity of the first location application.

7. A method as recited in claim 1, wherein the received transmission is identified as requiring multiple pass location processing based on a calling number of the wireless transmitter.

8. A method as recited in claim 1, further comprising identifying one or more location applications for which multiple pass location processing is required.

9. A method as recited in claim 1, wherein, in providing the first location estimate, the WLS selects a subset of the received transmission for use in providing a rough estimate of the location of the wireless transmitter.

10. A method as recited in claim 1, further comprising determining a priority level to be associated with location processing for the wireless transmitter.

11. A method as recited in claim 1, further comprising determining a time limit for signal collection for producing the first location estimate.

12. A method as recited in claim 1, further comprising determining a time limit for signal processing for producing the first location estimate.

13. A method as recited in claim 1, further comprising determining a time limit on total latency for providing the first location estimate.

14. A method as recited in claim 1, further comprising determining a signal power threshold.

15. A method as recited in claim 1, further comprising determining a time limit for delivery of a location estimate to the first location application.

16. A method as recited in claim 1, further comprising determining multiple location applications to which the first location estimate is to be provided.

17. A method as recited in claim 1, further comprising determining a time limit for signal collection for the second location estimate.

18. A method as recited in claim 1, further comprising determining a time limit for signal processing for the second location estimate.

19. A method as recited in claim 1, further comprising determining a time limit for total latency for the second location estimate.

20. A method recited in claim 1, further comprising determining a location accuracy threshold for the first location estimate.

21. A method as recited in claim 1, further comprising determining a velocity accuracy threshold for the first location estimate.

22. A method as recited in claim 1, wherein the second location estimate is independent of the first location estimate.

23. A method as recited in claim 1, wherein the first location estimate is used in deriving the second location estimate.

24. A method as recited in claim 1, wherein the first and second location estimates are derived in parallel.

25. A method as recited in claim 1, further comprising providing the second location estimate to the first location application.

26. A method as recited in claim 1, further comprising providing the second location estimate to a second location application, wherein the second location application is different from the first location application.

27. A method as recited in claim 1, further comprising providing multiple location estimates in step (b).

28. A method as recited in claim 1, wherein the first location estimate is provided with an information element identifying it as a lower quality estimate.

29. A method as recited in claim 1, wherein the second location estimate is provided with an information element identifying it as a higher quality estimate.

30. A multiple pass location processing method for use in a wireless location system (WLS) capable of locating a wireless transmitter involved in an emergency services call, based on a transmission received from the wireless transmitter, and routing the call to a call center, comprising the steps of:

(a) producing a first, lower quality location estimate and providing said first location estimate to a first location application; and

(b) producing a second location, higher quality location estimate;

wherein the first location estimate is less accurate than the second location estimate but is sufficient for call routing purposes.

31. A wireless location system (WLS), comprising:

(a) a plurality of geographically separated receiver systems for receiving a transmission from a wireless transmitter;

(b) means for producing a first, lower quality location estimate;

(c) means for providing said first location estimate to a first location application;

(d) means for producing a second, higher quality location estimate, wherein the second location estimate is characterized as being either more accurate or of a higher confidence than the first location estimate; and

(e) means for providing said second location estimate to the first or a second location application.

32. A WLS as recited in claim 31, wherein the second location estimate is a more accurate estimate than the first location estimate.

33. A WLS as recited in claim 31, wherein the second location estimate is of a higher confidence than the first location estimate.

34. A WLS as recited in claim 31, further comprising means for identifying a plurality of received transmissions as requiring multiple pass location processing.

35. A WLS as recited in claim 31, further comprising means for identifying one or more wireless transmitters as requiring multiple pass location processing.

36. A WLS as recited in claim 31, wherein the received transmission is identified as requiring multiple pass location processing based on the identity of the first location application.

37. A WLS as recited in claim 31, wherein the received transmission is identified as requiring multiple pass location processing based on a calling number of the wireless transmitter.

38. A WLS as recited in claim 31, further comprising means for identifying one or more location applications for which multiple pass location processing is required.

39. A WLS as recited in claim 31, wherein, in providing the first location estimate, the WLS selects a subset of the received transmission for use in providing a rough estimate of the location of the wireless transmitter.

40. A WLS as recited in claim 31, further comprising means for determining a priority level to be associated with location processing for the wireless transmitter.

41. A WLS as recited in claim 31, further comprising means for determining a time limit for signal collection for producing the first location estimate.

42. A WLS as recited in claim 31, further comprising means for determining a time limit for signal processing for producing the first location estimate.

43. A WLS as recited in claim 31, further comprising means for determining a time limit on total latency for providing the first location estimate.

44. A WLS as recited in claim 31, further comprising means for determining a signal power threshold.

45. A WLS as recited in claim 31, further comprising means for determining a time limit for delivery of a location estimate to the first location application.

46. A WLS as recited in claim 31, further comprising means for determining multiple location applications to which the first location estimate is to be provided.

47. A WLS as recited in claim 31, further comprising means for determining a time limit for signal collection for the second location estimate.

48. A WLS as recited in claim 31, further comprising means for determining a time limit for signal processing for the second location estimate.

49. A WLS as recited in claim 31, further comprising means for determining a time limit for total latency for the second location estimate.

50. A WLS as recited in claim 31, further comprising means for determining a location accuracy threshold for the first location estimate.

51. A WLS as recited in claim 31, further comprising means for determining a velocity accuracy threshold for the first location estimate.

52. A WLS as recited in claim 31, wherein the second location estimate is independent of the first location estimate.

53. A WLS as recited in claim 31, wherein the first location estimate is used in deriving the second location estimate.

54. A WLS as recited in claim 31, wherein the first and second location estimates are derived in parallel.

55. A WLS as recited in claim 31, further comprising means for providing the second location estimate to the first location application.

56. A WLS as recited in claim 31, further comprising means for providing the second location estimate to a second location application, wherein the second location application is different from the first location application.

57. A WLS as recited in claim 31, further comprising means for providing multiple location estimates.

58. A WLS as recited in claim 31, wherein the first location estimate is provided with an information element identifying it as a lower quality estimate.

59. A WLS as recited in claim 31, wherein the second location estimate is provided with an information element identifying it as a higher quality estimate.

60. A WLS as recited in claim 31, wherein the WLS supports multiple pass location processing with multiple pass location records in which a flag is included to indicate a maximum time limit before which a particular application must receive a rough estimate of location and a second maximum time limit in which the same or another application must receive a final location estimate.

61. A WLS as recited in claim 31, wherein a flag is included in a location record to indicate the first pass or second pass status of the location estimate contained in the record.

62. A multiple pass location processing means for use in a wireless location system (WLS) capable of locating a wireless transmitter involved in an emergency services call, based on a transmission received from the wireless transmitter, and routing the call to a call center, comprising:

(a) means for producing a first, lower quality location estimate and providing said first location estimate to a first location application; and

(b) means for producing a second, higher quality location estimate;

wherein the first location estimate is less accurate than the second location estimate but is sufficient for call routing purposes.

63. A multiple pass location processing means as recited in claim 62, further comprising a means for identifying transmissions for which a first, lower quality estimate is required, including multiple pass location records in which a flag is included to indicate a maximum time limit before which a particular application must receive a rough estimate of location and a second maximum time limit in which the same or another application must receive a final location estimate.

64. A multiple pass location processing means as recited in claim 62, wherein a flag is included in a location record to indicate the first pass or second pass status of the location estimate contained in the record.

65. A wireless location system (WLS), comprising:

(a) a plurality of geographically separated receiver systems for receiving a transmission from a wireless transmitter; and

(b) a processor and executable instructions for producing a first, lower quality location estimate, and for subsequently producing a second, higher quality location estimate, wherein said first location estimate may be communicated to a first location application for call routing purposes.

66. A method for use in a Wireless Location System in locating a mobile transmitter involved in an emergency services call and routing the call to the correct call center using a first location attempt bounded by the time to produce a first timely but lower accuracy location estimate for routing and a second location estimate bounded by the accuracy required for the purposes of caller location.

67. A method as recited in claim 66, wherein a site density factor is employed in determining the amount of signal collection andlor signal processing to use to produce the first location estimate.

68. A method as recited in claim 66, wherein a site density factor is employed in determining the scheduling of receiver resources to use to produce the first location estimate.

69. A method as recited in claim 66, wherein a site density factor is employed in determining the amount of signal collection and/or signal processing to use to produce the second location estimate.

70. A method as recited in claim 69, wherein a site density factor is employed in determining the scheduling of receiver resources to use to produce the second location estimate.