Method and apparatus for location determination in a wireless assisted hybrid positioning system

• US 20040002344A1
• Filed: 04/24/2003
• Published: 01/01/2004
• Est. Priority Date: 04/25/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Riley, Wyatt, Moeglein, Mark
• Granted Patent: US 7,460,870 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0257 Hybrid positioning by coordinating position lines of different shape G01S5/12
• 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: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

Methods and apparatuses for location determination in wireless assisted positioning systems. In one aspect of the disclosed method and apparatus, a method to determine a position of a mobile device in a positioning system includes: computing a second estimated position of a mobile device using a first assumed geometric relationship for a location of the mobile device in relation to a navigational transmitter (e.g., a basestation, a pseudolite, or a Satellite Positioning System (SPS) satellite). The first geometric relationship is linearly independent from the altitude of the mobile device (e.g., obtained from an altitude aiding) and a second geometric relationship based on range information (e.g., a range from the mobile device to the navigational transmitter, a pseudorange, an arrival time, or a round trip time) measured with respect to the navigational transmitter. In another embodiment of the disclosed method and apparatus, the method to determine a position of a mobile device in a positioning system includes: determining an estimated clock bias from a strength indicator of a signal transmitted from a navigational transmitter to the mobile device.

Claims

1. A method to determine a position of a mobile device in a positioning system, the method comprising:

computing a second estimated position of a mobile device using a first assumed geometric relationship for a location of the mobile device in relation to a navigational transmitter, the first geometric relationship being linearly independent from an altitude of the mobile device and a second geometric relationship based on range information measured with respect to the navigational transmitter.

2. A method as in claim 1 wherein the first geometric relationship is weighted against a third relationship for determining the second estimated position;

and wherein a weight for the first geometric relationship is dependent on a distance from a first estimated position of the mobile device to the navigational transmitter.

3. A method as in claim 2 wherein the weight for the first geometric relationship increases as the distance from the first estimated position to the navigational transmitter decreases.

4. A method as in claim 2 wherein a weight for the third relationship decreases as the distance from the first estimated position to the navigational transmitter decreases.

5. A method as in claim 1 wherein the range information is one of:

a) a range from the mobile device to the navigational transmitter;

b) a pseudorange;

c) a arrival time; and

d) a round trip time.

6. A method as in claim 5 wherein the navigational transmitter is one of:

a) a basestation;

b) a pseudolite; and

c) a Satellite Positioning System (SPS) satellite.

7. A method as in claim 1 wherein the first geometric relationship is assumed for a correction vector related to a difference between a first estimated position of the mobile device and the second estimated position;

and wherein the second estimated position is computed from the correction vector and the first estimated position.

8. A method as in claim 7 wherein the first geometric relationship specifies a first component of the correction vector along a first direction that is not parallel to a second direction pointing from the navigational transmitter to the first estimated position.

9. A method as in claim 8 wherein the first direction is orthogonal to the second direction and the first component of the correction vector is zero.

10. A method as in claim 8 further comprising:

computing coefficients of a linear equation for specifying the first component of the correction vector; and

determining the correction vector using the coefficients of the linear equation.

11. A method as in claim 10 wherein the first direction is orthogonal to a direction for defining an altitude of the mobile device.

12. A method as in claim 7 wherein the first geometric relationship is weighted against other relations for determining the correction vector.

13. A method as in claim 12 wherein a weight for the first geometric relationship is determined from at least one of:

a) an estimated error in a clock bias of the mobile device;

b) an estimated error in on the range information measured with respect to the navigational transmitter; and

c) an estimated range from the navigational transmitter to the first estimated position of the mobile device.

14. A method as in claim 7 wherein the first estimated position is obtained from a direction determined by an antenna of the navigational transmitter.

15. A method to determine a position of a mobile device in a positioning system, the method comprising:

determining an estimated clock bias from a strength indicator of a signal transmitted from a navigational transmitter to the mobile device.

16. A method as in claim 15 wherein the navigational transmitter is one of:

a) a basestation; and

b) a pseudolite.

17. A method as in claim 15 further comprising:

determining an estimated position of the mobile device using the estimated clock bias.

18. A method as in claim 17 wherein the estimated clock bias is weighted against other constraints in determining the estimated position of the mobile device.

19. A method as in claim 15 wherein the strength indicator is an Estimated Input Power (EIP).

20. A method as in claim 19 wherein said determining the estimated clock bias comprises:

receiving parameters from the navigational transmitter; and

computing the Estimated Input Power (EIP) from the parameters.

21. A method as in claim 20 wherein the parameters comprise at least one of:

a) Ec/I0; and

b) total pilot power.

22. A machine readable media containing executable computer program instructions which when executed by a digital processing system cause said system to perform a method to determine a position of a mobile device in a positioning system, the method comprising:

computing a second estimated position of a mobile device using a first assumed geometric relationship for a location of the mobile device in relation to a navigational transmitter, the first geometric relationship being linearly independent from an altitude of the mobile device and a second geometric relationship based on range information measured with respect to the navigational transmitter.

23. A media as in claim 22 wherein the first geometric relationship is weighted against a third relationship for determining the second estimated position;

and wherein a weight for the first geometric relationship is dependent on a distance from a first estimated position of the mobile device to the navigational transmitter.

24. A media as in claim 23 wherein the weight for the first geometric relationship increases as the distance from the first estimated position to the navigational transmitter decreases.

25. A media as in claim 23 wherein weights for the third relationship decreases as the distance from the first estimated position to the navigational transmitter decreases.

26. A media as in claim 22 wherein the range information is one of:

a) a range from the mobile device to the navigational transmitter;

b) a pseudorange;

c) a arrival time; and

d) a round trip time.

27. A media as in claim 26 wherein the navigational transmitter is one of:

a) a basestation;

b) a pseudolite; and

c) a Satellite Positioning System (SPS) satellite.

28. A media as in claim 22 wherein the first geometric relationship is assumed for a correction vector related to a difference between a first estimated position of the mobile device and the second estimated position;

and wherein the second estimated position is computed from the correction vector and the first estimated position.

29. A media as in claim 28 wherein the first geometric relationship specifies a first component of the correction vector along a first direction that is not parallel to a second direction pointing from the navigational transmitter to the first estimated position.

30. A media as in claim 29 wherein the first direction is orthogonal to the second direction and the first component of the correction vector is zero.

31. A media as in claim 29 wherein the method further comprises:

computing coefficients of a linear equation for specifying the first component of the correction vector; and

determining the correction vector using the coefficients of the linear equation.

32. A media as in claim 31 wherein the first direction is orthogonal to a direction for defining an altitude of the mobile device.

33. A media as in claim 28 wherein the first geometric relationship is weighted against other relations for determining the correction vector.

34. A media as in claim 33 wherein a weight for the first geometric relationship is determined from at least one of:

a) an estimated error in a clock bias of the mobile device;

b) an estimated error in on the range information measured with respect to the navigational transmitter; and

c) an estimated range from the navigational transmitter to the first estimated position of the mobile device.

35. A media as in claim 28 wherein the first estimated position is obtained from a direction determined by an antenna of the navigational transmitter.

44. A digital processing system as in claim 22 wherein the first geometric relationship is weighted against a third relationship for determining the second estimated position;

and wherein a weight for the first geometric relationship is dependent on a distance from a first estimated position of the mobile device to the navigational transmitter.

45. A digital processing system as in claim 23 wherein the weight for the first geometric relationship increases as the distance from the first estimated position to the navigational transmitter decreases.

46. A digital processing system as in claim 23 wherein weights for the third relationship decreases as the distance from the first estimated position to the navigational transmitter decreases.

36. A machine readable media containing executable computer program instructions which when executed by a digital processing system cause said system to perform a method to determine a position of a mobile device in a positioning system, the method comprising:

determining an estimated clock bias from a strength indicator of a signal transmitted from a navigational transmitter to the mobile device.

37. A media as in claim 36 wherein the navigational transmitter is one of:

a) a basestation; and

b) a pseudolite.

38. A media as in claim 36 further comprising:

determining an estimated position of the mobile device using the estimated clock bias.

39. A media as in claim 38 wherein the estimated clock bias is weighted against other constraints in determining the estimated position of the mobile device.

40. A media as in claim 36 wherein the strength indicator is an Estimated Input Power (EIP).

41. A media as in claim 40 wherein said determining the estimated clock bias comprises:

receiving parameters from the navigational transmitter; and

computing the Estimated Input Power (EIP) from the parameters.

42. A media as in claim 41 wherein the parameters comprise at least one of:

a) Ec/I0; and

b) total pilot power.

43. A digital processing system to determine a position of a mobile device in a positioning system, the processing system comprising:

means for computing a second estimated position of a mobile device using a first assumed geometric relationship for a location of the mobile device in relation to a navigational transmitter, the first geometric relationship being linearly independent from an altitude of the mobile device and a second geometric relationship based on range information measured with respect to the navigational transmitter.

47. A digital processing system as in claim 43 wherein the range information is one of:

a) a range from the mobile device to the navigational transmitter;

b) a pseudorange;

c) an arrival time; and

d) a round trip time.

48. A digital processing system as in claim 47 wherein the navigational transmitter is one of:

a) a basestation;

b) a pseudolite; and

c) an Satellite Positioning System (SPS) satellite.

49. A digital processing system as in claim 43 wherein the first geometric relationship is assumed for a correction vector related to a difference between a first estimated position of the mobile device and the second estimated position;

and wherein the second estimated position is computed from the correction vector and the first estimated position.

50. A digital processing system as in claim 49 wherein the first geometric relationship specifies a first component of the correction vector along a first direction that is not parallel to a second direction pointing from the navigational transmitter to the first estimated position.

51. A digital processing system as in claim 50 wherein the first direction is orthogonal to the second direction and the first component of the correction vector is zero.

52. A digital processing system as in claim 50 further comprising:

means for computing coefficients of a linear equation for specifying the first component of the correction vector; and

means for determining the correction vector using the coefficients of the linear equation.

53. A digital processing system as in claim 52 wherein the first direction is orthogonal to a direction for defining an altitude of the mobile device.

54. A digital processing system as in claim 49 wherein the first geometric relationship is weighted against other relations for determining the correction vector.

55. A digital processing system as in claim 54 wherein a weight for the first geometric relationship is determined from at least one of:

a) an estimated error in a clock bias of the mobile device;

b) an estimated error in on the range information measured with respect to the navigational transmitter; and

c) an estimated range from the navigational transmitter to the first estimated position of the mobile device.

56. A digital processing system as in claim 49 wherein the first estimated position is obtained from a direction determined by an antenna of the navigational transmitter.

57. A digital processing system to determine a position of a mobile device in a positioning system, the processing system comprising:

means for determining an estimated clock bias from a strength indicator of a signal transmitted from a navigational transmitter to the mobile device.

58. A digital processing system as in claim 57 wherein the navigational transmitter is one of:

a) a basestation; and

b) a pseudolite.

59. A digital processing system as in claim 57 further comprising:

means for determining an estimated position of the mobile device using the estimated clock bias.

60. A digital processing system as in claim 59 wherein the estimated clock bias is weighted against other constraints in determining the estimated position of the mobile device.

61. A digital processing system as in claim 57 wherein the strength indicator is an Estimated Input Power (EIP).

62. A digital processing system as in claim 61 wherein said means for determining the estimated clock bias comprises:

means for receiving parameters from the navigational transmitter; and

means for computing the Estimated Input Power (EIP) from the parameters.

63. A digital processing system as in claim 62 wherein the parameters comprise at least one of:

a) Ec/I0; and

b) total pilot power.