System and/or method for determining sufficiency of pseudorange measurements

• US 20070268177A1
• Filed: 08/24/2006
• Published: 11/22/2007
• Est. Priority Date: 05/19/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rowitch, Douglas Neal, Ahmed, Rizwan
• Granted Patent: US 7,656,348 B2
• Time in Patent Office: Days
• US Class Current: 342/357.430
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073

Abstract

The subject matter disclosed herein relates to a system and method for determining a sufficiency of measurements for locating positions. In one example, although claimed subject matter is not so limited, a process to improve accuracy of pseudorange measurements may be terminated in response to a weighting of quantitative assessments of at least some of such pseudorange measurements.

Claims

1. A method comprising:

determining quantitative assessments of accuracy associated with a plurality of pseudorange measurements to space vehicles (SVs) at a location; and

selectively terminating a process to improve said accuracy of said plurality of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to geometries associated with said SVs.

2. The method of claim 1, and further comprising determining said quantitative assessments of said accuracy associated with said plurality of said pseudorange measurements based, at least in part, on root mean square error estimates associated with said pseudorange measurements.

3. The method of claim 1, and further comprising determining said weighting of at least some of said quantitative measurements based, at least in part, on elevation angles associated with locations of said SVs.

4. The method of claim 3, and further comprising determining said weighting of at least some of said quantitative measurements based, at least in part, on azimuth angles associated with said locations of said SVs.

5. The method of claim 1, wherein said weighting of at least some of said quantitative assessments comprises a weighted horizontal dilution of precision.

6. The method of claim 1, wherein said process to improve said accuracy of said plurality of said pseudorange measurements comprises processing signals received from at least some of said SVs over a dwell.

7. The method of claim 1, wherein said selectively exiting said process to improve said accuracy of said plurality of pseudorange measurements further comprises:

combining said weighted quantitative assessments to provide a metric; and

selectively terminating said process to improve said accuracy in response to a comparison of said metric with a threshold value.

8. A method comprising:

determining a plurality of pseudorange measurements to space vehicles (SVs) at a location based, at least in part, on information received during a first dwell;

determining quantitative assessments of accuracy associated with said plurality of pseudorange measurements; and

selectively employing a second dwell to improve accuracy of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to geometries associated with said SVs.

9. An apparatus comprising:

a computing platform, said computing platform being adapted to;

determine quantitative assessments of accuracy associated with a plurality of pseudorange measurements to space vehicles (SVs) at a location; and

selectively terminate a process to improve said accuracy of said plurality of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to geometries associated with said SVs.

10. The apparatus of claim 9, wherein said computing platform is further adapted to determine said quantitative assessments of said accuracy associated with said plurality of said pseudorange measurements based, at least in part, on root mean square error estimates associated with said pseudorange measurements.

11. The apparatus of claim 9, wherein said computing platform is further adapted to determine said weighting of at least some of said quantitative measurements based, at least in part, on elevation angles associated with locations of said SVs.

12. The apparatus of claim 11, wherein said computing platform is further adapted to determine said weighting of at least some of said quantitative measurements based, at least in part, on azimuth angles associated with said locations of said SVs.

13. The apparatus of claim 9, wherein said weighting of at least some of said quantitative assessments comprises a weighted horizontal dilution of precision.

14. The apparatus of claim 9, wherein said process to improve said accuracy of said plurality of said pseudorange measurements comprises processing signals received from at least some of said SVs over a dwell.

15. The apparatus of claim 9, wherein said computing platform is further adapted to:

combine said weighted quantitative assessments to provide a metric; and

selectively terminate said process to improve said accuracy in response to a comparison of said metric with a threshold value.

16. An apparatus comprising:

a computing platform, said computing platform being adapted to;

determine a plurality of pseudorange measurements to space vehicles (SVs) at a location based, at least in part, on information received during a first dwell;

determine quantitative assessments of accuracy associated with said plurality of pseudorange measurements; and

selectively initiate a second dwell to improve accuracy of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to geometries associated with said SVs.

17. An article comprising:

a storage medium comprising machine-readable instructions stored thereon which, when executed, are adapted to;

determine quantitative assessments of accuracy associated with a plurality of pseudorange measurements to space vehicles (SVs) at a location; and

selectively terminate a process to improve said accuracy of said plurality of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to geometries associated with said SVs.

18. The article of claim 17, wherein said machine-readable instructions, when executed, are further adapted to determine said quantitative assessments of said accuracy associated with said plurality of said pseudorange measurements based, at least in part, on root mean square error estimates associated with said pseudorange measurements.

19. The article of claim 17, wherein said machine-readable instructions, when executed, are further adapted to determine said weighting of at least some of said quantitative measurements based, at least in part, on elevation angles associated with locations of said SVs.

20. The article of claim 19, wherein said machine-readable instructions, when executed, are further adapted to determine said weighting of at least some of said quantitative measurements based, at least in part, on azimuth angles associated with said locations of said SVs.

21. The article of claim 17, wherein said weighting of at least some of said quantitative assessments comprises a weighted horizontal dilution of precision.

22. The article of claim 17, wherein said process to improve said accuracy of said plurality of said pseudorange measurements comprises processing signals received from at least some of said SVs over a dwell.

23. The article of claim 17, wherein said machine-readable instructions, when executed, are further adapted to:

combine said weighted quantitative assessments to provide a metric; and

selectively terminate said process to improve said accuracy in response to a comparison of said metric with a threshold value.

24. An article comprising:

a storage medium comprising machine-readable instructions stored thereon which, when executed, are adapted to;

determine a plurality of pseudorange measurements to space vehicles (SVs) at a location based, at least in part, on information received during a first dwell;

determine quantitative assessments of accuracy associated with said plurality of pseudorange measurements; and

selectively initiate a second dwell to improve accuracy of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to geometries associated with said SVs.

25. A system comprising:

a position determination entity (PDE); and

a subscriber unit, the subscriber unit being adapted to;

receive an acquisition assistance message from said PDE over a terrestrial wireless communication link, said acquisition assistance message comprising information indicative of geometries associated with space vehicles (SVs);

determine quantitative assessments of accuracy associated with a plurality of pseudorange measurements to at least some of said SVs; and

selectively terminate a process to improve said accuracy of said plurality of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to said information.

26. A position determination entity comprising:

a receiver to receive pseudorange measurements to space vehicles (SVs) from a subscriber station over a data link, said position determination entity being adapted to;

determine quantitative assessments of accuracy associated with at least some of said received pseudorange measurements;

selectively terminate a process to improve said accuracy of said plurality of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to geometries associated with said SVs.

27. The position determination entity of claim 26, wherein said position determination entity is further adapted to determine said quantitative assessments of said accuracy associated with said plurality of said pseudorange measurements based, at least in part, on root mean square error estimates associated with said pseudorange measurements.

28. The position determination entity of claim 26, wherein said position determination entity is further adapted to determine said weighting of at least some of said quantitative measurements based, at least in part, on elevation angles associated with locations of said SVs.

29. The position determination entity of claim 28, wherein said position determination entity is further adapted to determine said weighting of at least some of said quantitative measurements based, at least in part, on azimuth angles associated with said locations of said SVs.

30. The position determination entity of claim 26, wherein said position determination entity is further adapted to:

combine said weighted quantitative assessments to provide a metric; and

selectively terminate said process to improve said accuracy in response to a comparison of said metric with a threshold value.

31. The position determination entity of claim 26, and further comprising a transmitter to transmit a message to said subscriber station to terminate said process.

32. A position determination entity comprising:

a receiver to receive pseudorange measurements to space vehicles (SVs) from a subscriber station over a data link, said position determination entity being adapted to;

determine a plurality of pseudorange measurements to space vehicles (SVs) at a location based, at least in part, on information received during a first dwell;

determine quantitative assessments of accuracy associated with said plurality of pseudorange measurements; and

selectively initiate a second dwell at said subscriber station to improve accuracy of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to geometries associated with said SVs.

33. A subscriber unit comprising:

receiver to receive an acquisition assistance (AA) message from a data link, said AA message comprising information indicative of geometries associated with space vehicles (SVs), said subscriber unit being adapted to;

determine quantitative assessments of accuracy associated with a plurality of pseudorange measurements to at least some of said SVs; and

selectively terminate a process to improve said accuracy of said plurality of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to said information.

34. The subscriber station of claim 33, wherein said subscriber station is further adapted to determine said quantitative assessments of said accuracy associated with said plurality of said pseudorange measurements based, at least in part, on root mean square error estimates associated with said pseudorange measurements.

35. The subscriber station of claim 33, wherein said subscriber station is further adapted to determine said weighting of at least some of said quantitative measurements based, at least in part, on approximations of elevation angles associated with locations of said SVs received in said AA message.

36. The subscriber station of claim 35, wherein said subscriber station is further adapted to determine said weighting of at least some of said quantitative measurements based, at least in part, on approximation of said azimuth angles associated with said locations of said SVs received in said AA message.

37. The subscriber station of claim 33, wherein said process to improve said accuracy of said plurality of said pseudorange measurements comprises processing signals received from at least some of said SVs over a dwell.

38. The subscriber station of claim 33, wherein said subscriber station is further adapted to:

combine said weighted quantitative assessments to provide a metric; and

selectively terminate said process to improve said accuracy in response to a comparison of said metric with a threshold value.

39. A subscriber unit comprising:

receiver to receive an acquisition assistance (AA) message from a data link, said AA message comprising information indicative of geometries associated with space vehicles (SVs), said subscriber unit being adapted to;

determine a plurality of pseudorange measurements to space vehicles (SVs) at a location based, at least in part, on information received during a first dwell;

determine quantitative assessments of accuracy associated with said plurality of pseudorange measurements; and

selectively initiate a second dwell to improve accuracy of said pseudorange measurements in response to a weighting of at least some of said quantitative assessments according to said information.