Mobile terminal and system and method for determining the geographic location of a mobile terminal

• US 6,433,735 B1
• Filed: 12/26/2000
• Issued: 08/13/2002
• Est. Priority Date: 12/26/2000
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bloebaum, L. Scott, McMahan, David
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/748,368
• Publication Number:
  US 20020080063A1
• Time in Patent Office: 595 Days
• Field of Search: 342/357.01, 342/357.06, 342/357.1, 342/357.13, 342/457, 455/422, 455/456, 701/213, 701/215
• US Class Current: 342/357.43
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset

Abstract

A mobile terminal and system and method for determining the geographic location of the mobile terminal. A current cell identification number is determined for a cell in which the mobile terminal is located. The geographic location of the mobile terminal is determined based on data including at least one geographic position stored in a database and associated in the database with data representing the current cell identification number. The database may be updated with the geographic location and the current cell identification number.

Claims

1. A mobile terminal comprising:

a positioning receiver; and

a processor circuit configured to identify an approximate geographic position of said mobile terminal by accessing a database comprising data representing a plurality of geographic positions provided by said positioning receiver, said approximate position corresponding to one of said geographic positions associated in said database with data representing a current cell identification number for a cell in which said mobile terminal is located.

2. A mobile terminal according to claim 1, wherein said is database stored in said mobile terminal.

3. A mobile terminal according to claim 1, wherein said processor is configured to compute a current geographic position based on data comprising said approximate position.

4. A mobile terminal according to claim 3, wherein said processor is configured to update said database with said current geographic position, said current geographic position being associated in said database with said current cell identification number.

5. A mobile terminal according to claim 3, wherein said processor is configured to compute said current geographic position at a predefined time interval.

6. A mobile terminal according to claim 3, wherein said processor is configured to compute said current geographic position when mobile terminal moves from a first cell to a second cell.

7. A mobile terminal according to claim 1, wherein said processor is configured to compute a current geographic position based on data comprising said approximate position and a positioning signal from a positioning signal source.

8. A mobile terminal according to claim 7, wherein said positioning signal source is a location server for a radio network communicating with said mobile terminal.

9. A mobile terminal according to claim 7, wherein said positioning signal source is a positioning system satellite.

10. A mobile terminal according to claim 9, wherein said satellite is a GPS satellite.

11. A mobile terminal according to claim 1, wherein said database employs a caching strategy.

12. A mobile terminal according to claim 11, wherein said caching strategy is selected from the group consisting of:

least recently used, first-in first-out, and random discard.

13. A mobile terminal comprising:

a communication processor circuit configured to determine a current cell identification number for a cell in which said mobile terminal is located;

a positioning receiver comprising a positioning processor circuit;

a database comprising data representing a plurality of geographic positions provided by said positioning receiver;

said positioning processor further configured to identify an approximate geographic position of said mobile terminal, said approximate position corresponding to one of said geographic positions associated in said database with data representing said current cell identification number.

14. A mobile terminal according to claim 13, wherein said positioning processor is configured to compute a current geographic position based on data comprising said approximate position.

15. A mobile terminal according to claim 14, wherein said positioning processor is configured to update said database with said current geographic position, said current geographic position being associated in said database with said current cell identification number.

16. A mobile terminal according to claim 14, wherein said positioning processor is configured to compute said current geographic position at a predefined time interval.

17. A mobile terminal according to claim 14, wherein said positioning processor is configured to compute said current geographic position when mobile terminal moves from a first cell to a second cell.

18. A mobile terminal according to claim 13, wherein said positioning processor is configured to compute a current geographic position based on data comprising said approximate position and a positioning signal from a positioning signal source.

19. A mobile terminal according to claim 18, wherein said positioning signal source is a location server for a radio network communicating with said mobile terminal.

20. A mobile terminal according to claim 18, wherein said positioning signal source is a positioning system satellite.

21. A mobile terminal according to claim 20, wherein said satellite is a GPS satellite.

22. A mobile terminal according to claim 13, wherein said database employs a caching strategy.

23. A mobile terminal according to claim 22, wherein said caching strategy is selected from the group consisting of:

least recently used, first-in first-out, and random discard.

24. A communication system comprising:

a radio network comprising a plurality of base stations, each said base station serving a cell in said radio network;

a mobile terminal comprising a positioning receiver, said mobile terminal configured to receive communication signals from said radio network, said communication signals comprising data representing a current cell identification number corresponding to an associated one of said cells in which said mobile terminal is located; and

a database comprising data representing a plurality of geographic positions provided by said positioning receiver;

said mobile terminal being configured to identify an approximate geographic position of said mobile terminal by accessing said database, said approximate position corresponding to one of said geographic positions associated in said database with data representing said current cell identification number.

25. A system according to claim 24, wherein said database is stored in said mobile terminal.

26. A system according to claim 24, said system further comprising a location server configured to communicate with said mobile terminal through said radio network, said server storing positioning data and being adapted for selectively transmitting said positioning data to said mobile terminal.

27. A system according to claim 24, wherein said mobile terminal is configured to compute a current geographic position based on data comprising said approximate position.

28. A system according to claim 27, wherein said mobile terminal is configured to update said database with said current geographic position, said current geographic position being associated in said database with said current cell identification number.

29. A system according to claim 27, wherein said processor is configured to compute said current geographic position at a predefined time interval.

30. A system according to claim 27, wherein said processor is configured to compute said current geographic position when mobile terminal moves from a first cell to a second cell.

31. A system according to claim 24, wherein said system further comprises at least one positioning signal source, and wherein said mobile terminal is configured to compute a current geographic position based on data comprising said approximate position and a positioning signal from said positioning signal source.

32. A system according to claim 31, wherein said positioning signal source is a location server configured to communicate with said mobile terminal through said radio network.

33. A system according to claim 31, wherein said positioning signal source is a positioning system satellite.

34. A system according to claim 33, wherein said satellite is a GPS satellite.

35. A system according to claim 24, wherein said database employs a caching strategy.

36. A system according to claim 35, wherein said caching strategy is selected from the group consisting of:

least recently used, first-in first-out, and random discard.

37. A communication system comprising:

radio network comprising a plurality of base stations, each said base station serving a cell in said radio network;

a mobile terminal comprising a positioning receiver and configured to receive communication signals from said radio network, said communication signals comprising data representing a current cell identification number corresponding to an associated one of said cells in which said mobile terminal is located;

a database comprising data representing a plurality of geographic positions provided by said positioning receiver; and

a location server configured to communicate with said mobile terminal through said radio network and to identify an approximate geographic position of said mobile terminal by accessing said database, said approximate position corresponding to one of said geographic positions associated in said database with data representing said current cell identification number.

38. A system according to claim 37, wherein said mobile terminal is configured to compute a current geographic position based on data comprising said approximate position.

39. A system according to claim 38, wherein said server is configured to update said database with said current geographic position, said current geographic position being associated in said database with said current cell identification number.

40. A system according to claim 38, wherein said mobile terminal is configured to compute said current geographic position at a predefined time interval.

41. A system according to claim 38, wherein said mobile terminal is configured to compute said current geographic position when mobile terminal moves from a first cell to a second cell.

42. A system according to claim 37, and wherein said mobile terminal is configured to compute a current geographic position based on data comprising said approximate position and a positioning signal from a positioning signal source.

43. A system according to claim 42, wherein said positioning signal source is a positioning system satellite.

44. A system according to claim 43, wherein said satellite is a GPS satellite.

45. A system according to claim 37, wherein said database employs a caching strategy.

46. A system according to claim 45, wherein said caching strategy is selected from the group consisting of:

least recently used, first-in first-out, and random discard.

47. A method of determining the geographic location of a mobile terminal comprising:

creating a database comprising data representing a plurality of geographic positions provided by a positioning receiver of said mobile terminal;

identifying a current cell identification number corresponding to a cell in which said mobile terminal is located; and

determining said geographic location based on data comprising one of said geographic positions associated in said database with data representing said current cell identification number.

48. A method according to claim 47, wherein said database is stored in said mobile terminal.

49. A method according to claim 47, wherein said database is stored in a location server configured to communicate with said mobile terminal through a radio network.

50. A method according to claim 47, wherein said current cell identification number is identified based on data received by said mobile terminal from a radio network.

51. A method according to claim 47, wherein said geographic position is determined by a processor in said mobile terminal.

52. A method according to claim 47, wherein said geographic position is determined by a location server configured to communicate with said mobile terminal through a radio network.

53. A method according to claim 47, wherein said data further comprises a positioning signal from a positioning signal source.

54. A method according to claim 53, wherein said positioning signal source is a location server configured to communicate with said mobile terminal through a radio network.

55. A method according to claim 53, wherein said positioning signal source is a positioning system satellite.

56. A method according to claim 55, wherein said satellite is a GPS satellite.

57. A method according to claim 47, wherein said data further comprises data selected from the group consisting of satellite orbits, time estimates, and ephemeris.

58. A method according to claim 47, said method further comprising:

updating said database with said geographic location.

59. A method according to claim 47, wherein said database employs a caching strategy.

60. A method according to claim 59, wherein said caching strategy is selected from the group consisting of:

least recently used, first-in first-out, and random discard.

61. A method according to claim 47, wherein said geographic location is determined at a predefined time interval.

62. A method according to claim 47, wherein said geographic location is determined when said mobile terminal moves from a first cell to a second cell.