System and/or method for reducing ambiguities in received SPS signals

• US 7,817,084 B2
• Filed: 08/21/2007
• Issued: 10/19/2010
• Est. Priority Date: 08/23/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Pon, Rayman Wai, Farmer, Dominic Gerard
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Mull; Fred H
• Application Number:
  US11/842,759
• Publication Number:
  US 20080079633A1
• Time in Patent Office: 1,155 Days
• Field of Search: 342/357.12, 342/357.15
• US Class Current: 342/357.73
• CPC Class Codes: G01S 19/243 Demodulation of navigation message
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data
• CPC Class Codes: G01S 19/33 Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS

Abstract

Systems, apparatuses, and/or methods for resolving ambiguities associated with signals received from space vehicles (SVs) in a satellite navigation system. For example, certain methods include receiving a first SV signal from a first satellite positioning system (SPS), and reducing a bit edge ambiguity of a data signal modulating a second SV signal received from a second SPS based, at least in part, on information in the received first SV signal.

Claims

1. A method comprising:

associating first pseudorange hypotheses derived from a first signal acquired from a first space vehicle (SV) at a reference location with one or more second pseudorange hypotheses derived from a second signal received from a second SV at said reference location, said associating being based, at least in part, on an estimated difference between a first range to said first SV from said reference location and a second range to said second SV from said reference location; and

reducing an ambiguity of a phase of a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first signal is transmitted according to a first format and said second signal is transmitted according to a second format different from said first format.

2. The method of claim 1, and further comprising determining said estimated difference based, at least in part, on locations of said first and second SVs.

3. The method of claim 2, and further comprising receiving information indicative of the locations of said first and second SVs obtained from an acquisition assistance message.

4. The method of claim 1, wherein said second signal is encoded with a repeating data sequence, and wherein said method further comprises:

decoding said repeating data sequence from at least a portion of said second signal; and

eliminating at least some of said second pseudorange hypotheses based, at least in part, on said decoded data sequence.

5. The method of claim 4, wherein said reducing said ambiguity further comprises:

limiting said associated first pseudorange hypotheses to first pseudorange hypotheses associated with any remaining second pseudorange hypotheses following said eliminating.

6. The method of claim 1, wherein said second signal is encoded with a known data sequence, and wherein said method further comprises:

detecting a phase alignment of said known data sequence relative to a true pseudorange to said second SV, and wherein said associating further comprises associating said true pseudorange to said second SV with said first pseudorange hypotheses.

7. A method comprising:

associating first pseudorange hypotheses derived from a first signal acquired from a first space vehicle (SV) at a reference location with one or more second pseudorange hypotheses derived from a second signal received from a second SV at said reference location, said associating being based, at least in part, on an estimated difference between a first range to said first SV from said reference location and a second range to said second SV from said reference location; and

reducing an ambiguity of a phase of a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first SV comprises a satellite in a GPS constellation and said second SV comprises a satellite in a Galileo constellation.

8. A method comprising:

determining a plurality of first pseudorange hypotheses to a first space vehicle (SV) from a reference location based, at least in part, on a first code phase detected in a first signal received at said reference location, said first signal being modulated by a data signal; and

reducing an ambiguity associated with a true pseudorange among said first pseudorange hypotheses with respect to said data signal based, at least in part, on a second code phase detected in a second signal received from a second SV at said reference location, wherein said first signal is transmitted according to a first format and second signal is transmitted according to a second format different from said first format.

9. The method of claim 8, wherein said second signal is encoded with a periodically repeating random code sequence, and wherein, said reducing said ambiguity further comprises:

determining one or more second pseudorange hypotheses to said second SV from said reference location based, at least in part, on said second code phase; and

associating said first hypotheses with said second hypotheses.

10. The method of claim 9, wherein said associating said first hypotheses with said second hypotheses further comprises associating said first hypotheses with said second hypotheses based, at least in part, on an estimate of a difference between a range to said first SV from said reference location and a range to said second SV from said reference location.

11. The method of claim 10, wherein said estimate is based, at least in part, on locations of said SVs.

12. The method of claim 9, wherein said second signal is modulated with information, and wherein said reducing said ambiguity further comprises eliminating said second pseudorange hypotheses based, at least in part, on said information.

13. The method of claim 12, wherein said information comprises a periodically repeating data sequence.

14. The method of claim 13, wherein said information comprises a Galileo pilot channel.

15. The method of claim 8, wherein said first SV is of a GPS constellation and said second SV is of a Galileo constellation.

16. A method comprising:

determining a plurality of first pseudorange hypotheses to a first space vehicle (SV) from a reference location based, at least in part, on a first code phase detected in a first signal received at said reference location, said first signal being modulated by a data signal; and

reducing an ambiguity associated with a true pseudorange among said first pseudorange hypotheses with respect to said data signal based, at least in part, on a second code phase detected in a second signal received from a second SV at said reference location, wherein said first signal is transmitted according to a first GNSS and second signal is transmitted according to a second GNSS different from said first GNSS.

17. A method comprising:

receiving a first space vehicle (SV) signal from a first satellite positioning system; and

reducing a bit edge ambiguity of a data signal modulating a second SV signal received from a second satellite positioning system based, at least in part, on information in said received first SV signal.

18. The method of claim 17, wherein said information comprises a code phase detected in said first SV signal.

19. The method of claim 18, wherein said reducing said bit edge ambiguity further comprises:

determining one or more first pseudorange hypotheses based, at least in part, on said code phase; and

associating said one or more first pseudorange hypotheses with a plurality of second pseudorange hypotheses associated with said second SV signal.

20. An article comprising:

a storage medium, said storage medium comprising machine-readable instructions stored thereon executable by a computing platform to;

associate first pseudorange hypotheses derived from a first signal acquired from a first space vehicle (SV) at a reference location with one or more second pseudorange hypotheses derived from a second signal received from a second SV at said reference location, said association between said first and second pseudorange hypotheses being based, at least in part, on an estimated difference between a first range to said first SV from said reference location and a second range to said second SV from said reference location; and

reduce an ambiguity of a phase of a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first signal is transmitted according to a first format and second signal is transmitted according to a second format different from said first format.

21. An article comprising:

a storage medium, said storage medium comprising machine-readable instructions stored thereon executable by a computing platform to;

determine a plurality of first pseudorange hypotheses to said first space vehicle (SV) from a reference location based, at least in part, on a first code phase detected in a first signal received at said reference location, said first signal being modulated by a data signal; and

reduce an ambiguity associated with a true pseudorange among said first pseudorange hypotheses with respect to said data signal based, at least in part, on a second code phase detected in a second signal received from a second SV at said reference location, wherein said first signal is transmitted according to a first format and second signal is transmitted according to a second format different from said first format.

22. An article comprising:

a storage medium, said storage medium comprising machine-readable instructions stored thereon executable by a computing platform to;

obtain information based, at least in part, on a first space vehicle (SV) signal received from a first satellite positioning system; and

reduce a bit edge ambiguity of a data signal modulating a second SV signal received from a second satellite positioning system based, at least in part, on information in said received first SV signal.

23. The article of claim 22, wherein said information comprises a code phase detected in said first SV signal.

24. The article of claim 23, said machine-readable instructions executable by a computing platform to further:

determine one or more first pseudorange hypotheses based, at least in part, on said code phase; and

associate said one or more first pseudorange hypotheses with a plurality of second pseudorange hypotheses associated with said second SV signal.

25. A subscriber unit comprising:

a receiver to receive an acquisition assistance (AA) message comprising information indicative of locations of first and second space vehicles (SVs); and

a processor to access said information indicative of said locations and to;

estimate a difference between a first range to said first SV from a reference location and a second range to said second SV from said reference location based, at least in part, on said information;

associate, based at least in part on said estimated difference, first pseudorange hypotheses derived from a first signal acquired from said first SV at a reference location with one or more second pseudorange hypotheses derived from a second signal acquired from said second SV at said reference location; and

reduce an ambiguity of a phase of a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first signal is transmitted according to a first format and second signal is transmitted according to a second format different from said first format.

26. The subscriber unit of claim 25, said receiver to receive said AA message over a terrestrial wireless communication link.

27. A subscriber unit comprising:

a receiver to receive an acquisition assistance (AA) message comprising information indicative of locations of first and second space vehicles (SVs); and

a processor to access said information indicative of said locations and to;

determine a plurality of first pseudorange hypotheses based, at least in part, on a first code phase detected in said first signal, said first signal being modulated by a data signal; and

reduce an ambiguity associated with a true pseudorange among said first pseudorange hypotheses with respect to said data signal based, at least in part, on said information and a second code phase detected in said second signal, wherein said first signal is transmitted according to a first format and second signal is transmitted to a second format different from said first format.

28. The subscriber unit of claim 27, said receiver to receive said AA message over a terrestrial wireless communication link.

29. A subscriber unit comprising:

a receiver to receive an acquisition assistance (AA) message comprising information indicative of locations of first and second space vehicle (SVs); and

a processor to access said information indicative of said locations and receive first and second SV signals, and reduce a bit edge ambiguity of a data signal modulating said second received SV signal based, at least in part, on information in said received first SV signal and said information indicative of said locations, wherein said received first signal is transmitted according to a first format and said received second signal is transmitted according to a second format different from said first format.

30. The subscriber unit of claim 29, said receiver receive said AA message over a terrestrial wireless communication link.

31. A system comprising:

a position determination entity (PDE); and

a subscriber unit to;

receive an acquisition assistance (AA) message from said PDE over a terrestrial wireless communication link, said AA message comprising information indicative of locations of first and second space vehicles (SVs);

estimate a difference between a first range from a reference location to said first SV and a second range from said reference location to said second SV based, at least in part, on said information;

associate, based at least in part on said estimated difference, first pseudorange hypotheses derived from a first signal acquired from said first SV at a reference location with one or more second pseudorange hypotheses derived from a second signal received from said second SV at said reference location; and

reduce an ambiguity of an alignment of a true pseudorange to said first SV relative to a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first signal is transmitted according to a first format and said second signal is transmitted according to a second format different from said first format.

32. A system comprising:

a position determination entity (PDE); and

a subscriber unit to;

receive an acquisition assistance (AA) message from said PDE over a terrestrial wireless communication link, said AA message comprising information indicative of locations of first and second space vehicles (SVs);

determine a plurality of first pseudorange hypotheses to said first space vehicle (SV) from a reference location based, at least in part, on a first code phase detected in a first signal received at said reference location, said first signal being modulated by a data signal; and

reduce an ambiguity associated with an alignment of a true pseudorange among said first pseudorange hypotheses with respect to said data signal based, at least in part, on a second code phase detected in a second signal received from a second SV at said reference location, wherein said first signal is transmitted according to a first format and second signal is transmitted according to a second format different from said first format.

33. A system comprising:

a position determination entity (PDE); and

a subscriber unit to;

receive an acquisition assistance (AA) message from said PDE over a terrestrial wireless communication link, said AA message comprising information indicative of locations of first and second space vehicles (SVs), said first SV being from a first satellite positioning system (SPS) and a second SV being from a second SPS;

receive a first SV signal from said first SV and a second SV signal from said second SV; and

reduce a bit edge ambiguity of a data signal modulating said second received SV signal based, at least in part, on information in said first received SV signal and said information indicative of said locations of said first and second SVs, wherein said first signal is transmitted according to a first format and second signal is transmitted according to a second format different from said first format.

34. An apparatus comprising:

means for receiving an acquisition assistance (AA) message comprising information indicative of locations of first and second space vehicles (SVs), said apparatus further comprising;

means for estimating a difference between a first range to said first SV from a reference location and a second range to said second SV from said reference location based, at least in part, on said information;

means for associating, based at least in part on said estimated difference, first pseudorange hypotheses derived from a first signal acquired from said first SV at a reference location with one or more second pseudorange hypotheses derived from a second signal acquired from said second SV at said reference location; and

means for reducing an ambiguity of a phase of a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first signal is transmitted according to a first format and second signal is transmitted according to a second format different from said first format.

35. The apparatus of claim 34, wherein said means for receiving is further adapted to receive said AA message over a terrestrial wireless communication link.

36. An apparatus comprising:

means for receiving a first space vehicle (SV) signal from a first satellite positioning system; and

means for reducing a bit edge ambiguity of a data signal modulating a second SV signal received from a second satellite positioning system based, at least in part, on information in said received first SV signal.

37. The apparatus of claim 36, wherein said information comprises a code phase detected in said first SV signal.

38. The apparatus of claim 37, further comprising:

means for determining one or more first pseudorange hypotheses based, at least in part, on said code phase; and

means for associating said one or more first pseudorange hypotheses with a plurality of second pseudorange hypotheses associated with said second SV signal.

39. An apparatus comprising:

a receiver to obtain a first space vehicle (SV) signal from a first satellite positioning system; and

a processor to reduce a bit edge ambiguity of a data signal modulating a second SV signal obtained from a second satellite positioning system based, at least in part, on information in said received first SV signal.

40. The apparatus of claim 39, wherein said information comprises a code phase detected in said first SV signal.

41. The apparatus of claim 40, the processor to further:

determine one or more first pseudorange hypotheses based, at least in part, on said code phase; and

associate said one or more first pseudorange hypotheses with a plurality of second pseudorange hypotheses associated with said second SV signal.

42. An article comprising:

a storage medium, said storage medium comprising machine-readable instructions stored thereon executable by a computing platform to;

associate first pseudorange hypotheses derived from a first signal acquired from a first space vehicle (SV) at a reference location with one or more second pseudorange hypotheses derived from a second signal received from a second SV at said reference location, said association between said first and second pseudorange hypotheses being based, at least in part, on an estimated difference between a first range to said first SV from said reference location and a second range to said second SV from said reference location; and

reduce an ambiguity of a phase of a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first SV comprises a satellite in a GPS constellation and said second SV comprises a satellite in a Galileo constellation.

43. An apparatus comprising:

means for associating first pseudorange hypotheses derived from a first signal acquired from a first space vehicle (SV) at a reference location with one or more second pseudorange hypotheses derived from a second signal received from a second SV at said reference location, said association between said first and second pseudorange hypotheses being based, at least in part, on an estimated difference between a first range to said first SV from said reference location and a second range to said second SV from said reference location; and

means for reducing an ambiguity of a phase of a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first SV comprises a satellite in a GPS constellation and said second SV comprises a satellite in a Galileo constellation.

44. An apparatus comprising:

a processor to;

associate first pseudorange hypotheses derived from a first signal acquired from a first space vehicle (SV) at a reference location with one or more second pseudorange hypotheses derived from a second signal received from a second SV at said reference location, said association between said first and second pseudorange hypotheses being based, at least in part, on an estimated difference between a first range to said first SV from said reference location and a second range to said second SV from said reference location, and

reduce an ambiguity of a phase of a bit edge of a data signal modulating said first signal based, at least in part, on said associated first pseudorange hypotheses, wherein said first SV comprises a satellite in a GPS constellation and said second SV comprises a satellite in a Galileo constellation.