System for automatically determining cell transmitter parameters to facilitate the location of wireless devices

• US 20080132247A1
• Filed: 12/01/2006
• Published: 06/05/2008
• Est. Priority Date: 12/01/2006
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: TruePosition Incorporated
• Inventors: Anderson, Robert J.
• Granted Patent: US 7,797,000 B2
• Time in Patent Office: Days
• US Class Current: 455/456.2
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0226 Transmitters
• 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: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Several techniques for locating wireless devices involve the Mobile Stations (MS) making measurements of the signals transmitted by geographically distributed base stations within a wireless network. If some key site information is known about these transmitters, such as the transmitter location, transmit signal power, signal propagation, and transmit signal timing, measurements of these transmit signals by a MS can be used to determine the position of the MS. An automatic method to detect transmitters, identify key transmitter information, and utilize the base station transmit signals to perform location is presented. In addition, this method facilitates the use of cell site transmit signals that are part of multiple wireless networks.

Claims

1. A system for locating a mobile wireless device, comprising:

a location processing node;

at least one wireless device, wherein said at least one wireless device is configured to communicate with said location processing node via a communications link, and to make scanning measurements of signals from one or more geographically distributed transmitters, wherein said at least one wireless device is further configured to assist the location processing node in determining key transmitter information by receiving and measuring characteristics of said signals and providing information about said characteristics via the communications link to said location processing node; and

a server configured to communicate with a wireless device to be located, and to cause said wireless device to be located to make signal measurements of signals from one or more transmitters and to provide measurement information to said location processing node;

wherein said characteristics measured by said at least one wireless device are useful, in combination with characteristics measured by other wireless devices, to determine the key transmitter information.

2. A system as recited in claim 1, wherein said at least one wireless device is further configured to communicate said key transmitter information to said location processing node, wherein said information may be used by said location processing node to compute the location of one or more wireless devices.

3. A system as recited in claim 1, wherein the system is configured to operate with said one or more transmitters, and wherein at least one transmitter is part of a first wireless communications network and a least one transmitter is part of a second wireless communications network.

4. A system as recited in claim 1, wherein said server is configured to communicate via a user plane data channel with said at least one wireless device, and wherein said wireless device is configured to provide measurement information via the data channel to said location processing node.

5. A system as recited in claim 1, wherein said key transmitter information includes cell identification information.

6. A system as recited in claim 5, wherein said cell identification information includes at least one member of the group consisting of Cell ID, frequency channel, base station identify code, Cell Global Identity, and Base Station ID.

7. A system as recited in claim 1, wherein said key transmitter information includes cell transmitter location information.

8. A system as recited in claim 7, wherein said cell transmitter location information includes latitude and longitude.

9. A system as recited in claim 1, wherein said key transmitter information includes cell transmitter signal timing information.

10. A system as recited in claim 1, wherein said signal measurements include relative signal timing.

11. A system as recited in claim 1, wherein said signal measurements include absolute signal timing.

12. A system as recited in claim 1, wherein said signal measurements include received power level.

13. A system as recited in claim 1, wherein said location processing node is programmed to compute a location solution based upon time difference measurements.

14. A system as recited in claim 1, wherein said at least one wireless device is a mobile device.

15. A system as recited in claim 1, wherein said at least one wireless device is a fixed device.

16. A system as recited in claim 1, wherein said at least one wireless device is at a known location.

17. A system as recited in claim 1, wherein said at least one wireless device is at an unknown location.

18. A system as recited in claim 1, wherein said location processing node is programmed to compute a location solution using said measurements and previously known information to solve for unknown information.

19. A system as recited in claim 1, wherein said location processing node is programmed to compute an error function based on known and unknown information, and to solve for the unknown information by minimizing the error function.

20. A system as recited in claim 19, wherein said location processing node is programmed to compute the error of each of the measurements as a function of the unknown information.

21. A system as recited in claim 20, wherein said location processing node is programmed to compute an error function for time difference measurements, wherein said error function is the difference between a measured time difference and a theoretical time difference, assuming a hypothesized set of transmitter positions, transmitter timing offsets and receiver positions.

22. A system as recited in claim 21, wherein said location processing node is programmed to compute the square error of each of the measurements based on the unknown information.

23. A system as recited in claim 22, wherein said location processing node is programmed to weight the square error of each of the measurements based on the quality of the measurement, and to sum the weighted errors to create a signal error value which is a function of the unknown data.

24. A system as recited in claim 23, wherein said location processing node is programmed to solve for the unknown data by minimizing the error function.

25. A system as recited in claim 24, wherein said location processing node is programmed to mark data as known once it determined, and using the known values to simplify the solution of unknown information.

26. A system as recited in claim 25, wherein the known information includes previously determined transmitter position information.

27. A system as recited in claim 25, wherein the known information includes timing of a transmitter known to be synchronous with respect to a common timing source.

28. A system as recited in claim 25, wherein the known information includes positions of fixed receivers.

29. A system as recited in claim 25, wherein the known information includes positions of mobile receivers.

30. A system as recited in claim 18, wherein said location processing node is programmed to limit a portion of the location solution to a geographic region, and to then later combine the data from various regions to simplify solution of the unknown data.

31. A system as recited in claim 1, wherein said location processing node comprises a computer.

32. A system as recited in claim 1, wherein said location processing node comprises a wireless device.

33. A system as recited in claim 1, wherein said at least one wireless device is further configured to communicate said key transmitter information to said location processing node, wherein said information is usable by said location processing node to compute the location of one or more wireless devices;

wherein said server is configured to communicate via a user plane data channel with said at least one wireless device, and wherein said wireless device to be located is configured to provide measurement information via the data channel to said location processing node;

wherein said key transmitter information includes cell identification information, cell transmitter location information, and cell transmitter signal timing information; and

wherein said signal measurements include signal timing and received power level.

34. A method for locating a mobile wireless device, comprising:

instructing at least one wireless device to communicate with a location processing node via a communications link, and to make scanning measurements of signals from one or more geographically distributed transmitters, and further instructing said at least one wireless device to assist the location processing node in determining key transmitter information by receiving and measuring characteristics of said signals and providing information about said characteristics via the communications link to said location processing node, wherein said characteristics are useful to determine the key transmitter information;

instructing a wireless device to be located to make signal measurements of signals from one or more transmitters and to provide measurement information to said location processing node; and

at the location processing node, using said key transmitter information and said measurement information to determine the geographic location of said wireless device to be located.

35. A method as recited in claim 34, comprising instructing said at least one wireless device to communicate said key transmitter information to said location processing node, wherein said information is used by said location processing node to compute the location of one or more wireless devices.

36. A method as recited in claim 34, wherein the method is performed with at least one transmitter of a first wireless communications network and a least one transmitter of a second wireless communications network.

37. A method as recited in claim 34, wherein communications between one or more wireless devices and said location processing node are conducted via a user plane data channel.

38. A method as recited in claim 34, wherein said key transmitter information includes cell identification information.

39. A method as recited in claim 38, wherein said cell identification information includes at least one member of the group consisting of Cell ID, frequency channel, base station identify code, Cell Global Identity, and Base Station ID.

40. A method as recited in claim 34, wherein said key transmitter information includes cell transmitter location information.

41. A method as recited in claim 40, wherein said cell transmitter location information includes latitude and longitude.

42. A method as recited in claim 34, wherein said key transmitter information includes cell transmitter signal timing information.

43. A method as recited in claim 34, wherein said signal measurements include relative signal timing.

44. A method as recited in claim 34, wherein said signal measurements include absolute signal timing.

45. A method as recited in claim 34, wherein said signal measurements include received power level.

46. A method as recited in claim 34, wherein said location processing node is programmed to compute a location solution based upon time difference measurements.

47. A method as recited in claim 34, wherein said at least one wireless device is a mobile device.

48. A method as recited in claim 34, wherein said at least one wireless device is a fixed device.

49. A method as recited in claim 34, wherein said at least one wireless device is at a known location.

50. A method as recited in claim 34, wherein said at least one wireless device is at an unknown location.

51. A method as recited in claim 34, wherein said location processing node is programmed to compute a location solution using said measurements and previously known information to solve for unknown information.

52. A method as recited in claim 34, wherein said location processing node is programmed to compute an error function based on known and unknown information, and to solve for the unknown information by minimizing the error function.

53. A method as recited in claim 52, wherein said location processing node is programmed to compute the error of each of the measurements as a function of the unknown information.

54. A method as recited in claim 53, wherein said location processing node is programmed to compute an error function for time difference measurements, wherein said error function is the difference between a measured time difference and a theoretical time difference, assuming a hypothesized set of transmitter positions, transmitter timing offsets and receiver positions.

55. A method as recited in claim 54, wherein said location processing node is programmed to compute the square error of each of the measurements based on the unknown information.

56. A method as recited in claim 55, wherein said location processing node is programmed to weight the square error of each of the measurements based on the quality of the measurement, and to sum the weighted errors to create a signal error value which is a function of the unknown data.

57. A method as recited in claim 56, wherein said location processing node is programmed to solve for the unknown data by minimizing the error function.

58. A method as recited in claim 57, wherein said location processing node is programmed to mark data as known once it determined, and using the known values to simplify the solution of unknown information.

59. A method as recited in claim 58, wherein the known information includes previously determined transmitter position information.

60. A method as recited in claim 58, wherein the known information includes timing of a transmitter known to be synchronous with respect to a common timing source.

61. A method as recited in claim 58, wherein the known information includes positions of fixed receivers.

62. A method as recited in claim 58, wherein the known information includes positions of mobile receivers.

63. A method as recited in claim 51, wherein said location processing node is programmed to limit a portion of the location solution to a geographic region, and to then later combine the data from various regions to simplify solution of the unknown data.

64. A method as recited in claim 34, wherein said location processing node comprises a computer.

65. A method as recited in claim 34, wherein said location processing node comprises a wireless device.

66. A method as recited in claim 34, wherein said at least one wireless device is further instructed to communicate said key transmitter information to said location processing node, wherein said information is used by said location processing node to compute the location of one or more wireless devices;

wherein said wireless devices are operative to communicate via a user plane data channel, and wherein said wireless device to be located is operative to provide measurement information via the data channel to said location processing node;

wherein said key transmitter information includes cell identification information, cell transmitter location information, and cell transmitter signal timing information; and

wherein said signal measurements include signal timing and received power level.

67. A wireless device configured to cooperate with a location processing node in carrying out a method for locating a mobile wireless device, comprising:

a processor; and

executable instructions for instructing the processor to control the wireless device in communicating with a location processing node, and making scanning measurements of signals from one or more geographically distributed transmitters, and assisting the location processing node in determining key transmitter information by receiving and measuring characteristics of said signals and providing information about said characteristics via a communications link to said location processing node.

68. A wireless device as recited in claim 67, further comprising executable instructions for instructing the processor to control the wireless device in making signal measurements of signals from one or more transmitters and to provide measurement information to said location processing node.

69. A wireless device as recited in claim 67, further comprising executable instructions for instructing the processor to control the wireless device in communicating said key transmitter information to said location processing node, wherein said information is used by said location processing node to compute the location of one or more wireless devices.

70. A wireless device as recited in claim 67, wherein the wireless device is configured to communicate with at least one transmitter of a first wireless communications network and a least one transmitter of a second wireless communications network.

71. A wireless device as recited in claim 67, wherein said wireless device is configured to communicate with said location processing node via a user plane data channel.

72. A wireless device as recited in claim 67, wherein said key transmitter information includes cell identification information.

73. A wireless device as recited in claim 72, wherein said cell identification information includes at least one member of the group consisting of Cell ID, frequency channel, base station identify code, Cell Global Identity, and Base Station ID.

74. A wireless device as recited in claim 67, wherein said key transmitter information includes cell transmitter location information.

75. A wireless device as recited in claim 74, wherein said cell transmitter location information includes latitude and longitude.

76. A wireless device as recited in claim 67, wherein said key transmitter information includes cell transmitter signal timing information.

77. A wireless device as recited in claim 67, wherein said signal measurements include relative signal timing.

78. A wireless device as recited in claim 67, wherein said signal measurements include absolute signal timing.

79. A wireless device as recited in claim 67, wherein said signal measurements include received power level.

80. A wireless device as recited in claim 67, wherein said wireless device is a mobile device.

81. A wireless device as recited in claim 67, wherein said wireless device is a fixed device.