Time-setting in satellite positioning system receivers

• US 8,571,089 B2
• Filed: 08/09/2010
• Issued: 10/29/2013
• Est. Priority Date: 08/09/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Hoang, Duong A., Rowitch, Douglas Neal, Wu, Jie, Simic, Emilija M., Farmer, Dominic Gerard
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): Bolourchi, Nader
• Application Number:
  US12/853,182
• Publication Number:
  US 20120033716A1
• Time in Patent Office: 1,177 Days
• Field of Search: 375/150
• US Class Current: 375/150
• CPC Class Codes: G01S 19/243 Demodulation of navigation message
• CPC Class Codes: G01S 19/246 involving long acquisition integration times, extended snapshots of signals or methods specifically directed towards weak signal acquisition
• CPC Class Codes: H04B 1/70758 Multimode search, i.e. using multiple search strategies
• CPC Class Codes: H04B 2201/70715 with application-specific features

Abstract

Techniques are provided which may be implemented using various methods and/or apparatuses in a receiver and/or other like device to determine an SPS time using SPS signals based on a correlation process. A verification process may be performed, for example, that verifies a maximum peak in comparison with other peak information resulting from the correlation process, for example, by considering a ratio of a maximum peak to a next maximum peak. A time-setting algorithm may be selected, for example, based, at least in part, on a time uncertainty and/or on a type of demodulation performed on the SPS signal. The time-setting algorithm may operatively control one or both of the correlation and/verification processes in a desired manner given the time uncertainty and/or type/mode of demodulation performed.

Claims

1. A method comprising:

with an electronic device;

receiving a sequence of bits from a Satellite Positioning System (SPS) signal comprising one or more data sub-frames;

selecting a time-setting algorithm from among a plurality of time-setting algorithms based, at least in part, on a time uncertainty;

correlating a known and/or predicted bit sequence with said received SPS signal at multiple time-shifted hypotheses;

verifying a maximum peak in comparison with other peak information resulting from said correlating;

detecting a sub-frame preamble in said received SPS signal based, at least in part, on results from said verified maximum peak; and

generating one or more electrical signals representing an SPS time based, at least in part, on a position of said detected sub-frame preamble in said sequence of bits,

wherein at least one of said correlating and/or said verifying is affected by said time-setting algorithm.

2. The method as recited in claim 1, wherein verifying said maximum peak further comprises:

verifying that a ratio of said maximum peak to a next maximum peak resulting from said correlating exceeds a threshold value.

3. The method as recited in claim 1, further comprising:

with said electronic device;

selecting said time-setting algorithm based, at least in part, on a time uncertainty threshold associated with the SPS signal.

4. The method as recited in claim 3, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates at least one of a listing process and/or a decoding process as part of said correlating.

5. The method as recited in claim 3, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates a relaxation process as part of said verifying.

6. The method as recited in claim 3, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates a re-verifying process.

7. The method as recited in claim 2, wherein said threshold value is based, at least in part, on at least one of:

a type of demodulation performed on said SPS signal;

a length of an integration period;

a number of space vehicles (SVs) associated with said SPS signal;

or

an estimated value of an SV'"'"'s Carrier-to-Noise power ratio (C/No).

8. The method as recited in claim 1, wherein said multiple time-shifted hypotheses are associated with bit positions, and wherein said detecting said sub-frame preamble comprises:

identifying a bit position associated with a peak correlation result.

9. The method as recited in claim 8, and wherein generating said one or more electrical signals representing said SPS time comprises associating said SPS time with said identified bit position.

10. The method as recited in claim 1, and further comprising:

with said electronic device;

receiving multiple bit streams from at least one of;

an associated multiple satellite vehicle (SV) transmitters, and/or an associated multiple sub-frames from one of said SV transmitters;

correlating said known and/or predicted bit sequence with each of said multiple bit streams at said multiple time-shifted hypotheses to provide an associated multiple correlation results for each time-shifted hypothesis;

for each time-shifted hypothesis, combining said associated multiple correlation results; and

identifying a bit position associated with each combined correlation result.

11. An apparatus for use in an electronic device, the apparatus comprising:

means for receiving a sequence of bits from a Satellite Positioning System (SPS) signal comprising one or more data sub-frames;

means for selecting a time-setting algorithm from among a plurality of time-setting algorithms based, at least in part, on a time uncertainty;

means for correlating a known and/or predicted bit sequence with said received SPS signal at multiple time-shifted hypotheses;

means for verifying a maximum peak in comparison with other peak information resulting from said correlating;

means for detecting a sub-frame preamble in said received SPS signal based, at least in part, on results from said verified maximum peak; and

means for determining a SPS time based, at least in part, on a position of said detected sub-frame preamble in said sequence of bits,

wherein at least one of said means for correlating and/or said means for verifying is affected by said time-setting algorithm.

12. The apparatus as recited in claim 11, wherein said means for verifying said maximum peak comprises means for verifying that a ratio of said maximum peak to a next maximum peak resulting from said correlating exceeds a threshold value.

13. The apparatus as recited in claim 11, further comprising:

means for selecting said time-setting algorithm based, at least in part, on a time uncertainty threshold associated with the SPS signal.

14. The apparatus as recited in claim 13, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates at least one of means for listing and/or means for decoding as part of said means for correlating.

15. The apparatus as recited in claim 14, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates means for relaxation as part of said means for verifying.

16. The apparatus as recited in claim 13, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates means for re-verifying process.

17. The apparatus as recited in claim 12, wherein said threshold value is based, at least in part, at least one of:

a type of demodulation performed on said SPS signal;

a length of an integration period;

a number of space vehicles (SVs) associated with said SPS signal;

or

an estimated value of an SV'"'"'s Carrier-to-Noise power ratio (C/No).

18. The apparatus as recited in claim 11, wherein said multiple time-shifted hypotheses are associated with bit positions, and wherein said means for detecting said sub-frame preamble comprises:

means for identifying a bit position associated with a peak correlation result.

19. The apparatus as recited in claim 11, and wherein said means for determining said SPS time comprises associating said SPS time with said identified bit position.

20. The apparatus as recited in claim 11, and further comprising:

means for receiving multiple bit streams from at least one of;

an associated multiple satellite vehicle (SV) transmitters, and/or an associated multiple sub-frames from one of said SV transmitters;

means for correlating said known and/or predicted bit sequence with each of said multiple bit streams at said multiple time-shifted hypotheses to provide an associated multiple correlation results for each time-shifted hypothesis;

for each time-shifted hypothesis, means for combining said associated multiple correlation results; and

means for identifying a bit position associated with each combined correlation result.

21. An apparatus comprising:

at least one processing unit to;

obtain a sequence of bits from a Satellite Positioning System (SPS) signal comprising one or more data sub-frames;

select a time-setting algorithm from among a plurality of time-setting algorithms based, at least in part, on a time uncertainty;

correlate a known and/or predicted bit sequence with said received SPS signal at multiple time-shifted hypotheses;

verify a maximum peak in comparison with other peak information resulting from said correlating;

detect a sub-frame preamble in said received SPS signal based, at least in part, on results from said verified maximum peak; and

determine a SPS time based, at least in part, on a position of said detected sub-frame preamble in said sequence of bits, wherein said time-selecting algorithm affects said at least one processing unit in performing at least one of said correlation and/or said verification.

22. The apparatus as recited in claim 21, said at least one processing unit to verify said maximum peak by verifying that a ratio of said maximum peak to a next maximum peak resulting from said correlating exceeds a threshold value.

23. The apparatus as recited in claim 21, said at least one processing unit to further select said time-setting algorithm based, at least in part, on a time uncertainty threshold associated with the SPS signal.

24. The apparatus as recited in claim 23, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates at least one of a listing process and/or a decoding process as part of said correlation.

25. The apparatus as recited in claim 23, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates a relaxation process as part of said verification.

26. The apparatus as recited in claim 23, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates a re-verifying process.

27. The apparatus as recited in claim 22, wherein said threshold value is based, at least in part, on at least one of:

a type of demodulation performed on said SPS signal;

a length of an integration period;

a number of space vehicles (SVs) associated with said SPS signal;

or

an estimated value of an SV'"'"'s Carrier-to-Noise power ratio (C/No).

28. The apparatus as recited in claim 21, wherein said multiple time-shifted hypotheses are associated with bit positions, and wherein said at least one processing unit to further identify a bit position associated with a peak correlation result.

29. The apparatus as recited in claim 28, and wherein said determining said SPS time comprises associating said SPS time with said identified bit position.

30. The apparatus as recited in claim 21, said at least one processing unit to further:

obtain multiple bit streams from at least one of;

an associated multiple satellite vehicle (SV) transmitters, and/or an associated multiple sub-frames from one of said SV transmitters;

correlate said known and/or predicted bit sequence with each of said multiple bit streams at said multiple time-shifted hypotheses to provide an associated multiple correlation results for each time-shifted hypothesis;

for each time-shifted hypothesis, combine said associated multiple correlation results; and

identify a bit position associated with each combined correlation result.

31. An article comprising:

a non-transitory computer readable medium having stored therein computer-implementable instructions executable by one or more processing units to;

obtain a sequence of bits from a Satellite Positioning System (SPS) signal comprising one or more data sub-frames;

select a time-setting algorithm from among a plurality of time-setting algorithms based, at least in part, on a time uncertainty;

correlate a known and/or predicted bit sequence with said received SPS signal at multiple time-shifted hypotheses;

verify a maximum peak in comparison with other peak information resulting from said correlating;

detect a sub-frame preamble in said received SPS signal based, at least in part, on results from said verified maximum peak; and

determine a SPS time based, at least in part, on a position of said detected sub-frame preamble in said sequence of bits,

wherein said time-selecting algorithm affects said one or more processing units in performing at least one of said correlation and/or said verification.

32. The article as recited in claim 31, said computer-implementable instructions being further executable by said one or more processing units to verify said maximum peak by verifying that a ratio of said maximum peak to a next maximum peak resulting from said correlating exceeds a threshold value.

33. The article as recited in claim 32, said computer-implementable instructions being further executable by said one or more processing units to further select said time-setting algorithm based, at least in part, on a time uncertainty threshold associated with the SPS signal.

34. The article as recited in claim 33, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates at least one of a listing process and/or a decoding process as part of said correlation.

35. The article as recited in claim 33, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates a relaxation process as part of said verification.

36. The article as recited in claim 33, wherein said time uncertainty exceeds a time uncertainty threshold and said selected time-setting algorithm selectively initiates a re-verifying process.

37. The article as recited in claim 32, wherein said threshold value is based, at least in part, at least one of:

a type of demodulation performed on said SPS signal;

a length of an integration period;

a number of space vehicles (SVs) associated with said SPS signal;

or

an estimated value of an SV'"'"'s Carrier-to-Noise power ratio (C/No).

38. The article as recited in claim 31, wherein said multiple time-shifted hypotheses are associated with bit positions, and wherein said at least one processing unit to further identify a bit position associated with a peak correlation result.

39. The article as recited in claim 38, and wherein said determining said SPS time comprises associating said SPS time with said identified bit position.

40. The article as recited in claim 31, said computer-implementable instructions being further executable by said one or more processing units to further:

obtain multiple bit streams from at least one of;

an associated multiple satellite vehicle (SV) transmitters, and/or an associated multiple sub-frames from one of said SV transmitters;

correlate said known and/or predicted bit sequence with each of said multiple bit streams at said multiple time-shifted hypotheses to provide an associated multiple correlation results for each time-shifted hypothesis;

for each time-shifted hypothesis, combine said associated multiple correlation results; and

identify a bit position associated with each combined correlation result.

41. A method comprising:

with an electronic device;

receiving a sequence of bits from a Satellite Positioning System (SPS) signal comprising one or more data sub-frames;

selecting a time-setting algorithm from among a plurality of time-setting algorithms based, at least in part, on a type of demodulation performed on said SPS signal;

correlating a known and/or predicted bit sequence with said received SPS signal at multiple time-shifted hypotheses;

verifying a maximum peak in comparison with other peak information resulting from said correlating;

detecting a sub-frame preamble in said received SPS signal based, at least in part, on results from said verified maximum peak; and

generating one or more electrical signals representing an SPS time based, at least in part, on a position of said detected sub-frame preamble in said sequence of bits,

wherein at least one of said correlating and/or said verifying is affected by said time-setting algorithm.

42. The method as recited in claim 41, wherein said type of demodulation performed on said SPS signal comprises at least one of coherent demodulation and non-coherent demodulation.

43. The method as recited in claim 41, and further comprising:

with said electronic device;

receiving multiple bit streams from at least one of;

an associated multiple satellite vehicle (SV) transmitters, and/or an associated multiple sub-frames from one of said SV transmitters;

correlating said known and/or predicted bit sequence with each of said multiple bit streams at said multiple time-shifted hypotheses to provide an associated multiple correlation results for each time-shifted hypothesis;

for each time-shifted hypothesis, combining said associated multiple correlation results; and

identifying a bit position associated with each combined correlation result.

44. An apparatus for use in an electronic device, the apparatus comprising:

means for receiving a sequence of bits from a Satellite Positioning System (SPS) signal comprising one or more data sub-frames;

means for selecting a time-setting algorithm from among a plurality of time-setting algorithms based, at least in part, on a type of demodulation performed on said SPS signal;

means for correlating a known and/or predicted bit sequence with said received SPS signal at multiple time-shifted hypotheses;

means for verifying a maximum peak in comparison with other peak information resulting from said correlating;

means for detecting a sub-frame preamble in said received SPS signal based, at least in part, on results from said verified maximum peak; and

means for determining a SPS time based, at least in part, on a position of said detected sub-frame preamble in said sequence of bits,

wherein at least one of said means for correlating and/or said means for verifying is affected by said time-setting algorithm.

45. The apparatus as recited in claim 44, wherein said type of demodulation performed on said SPS signal comprises at least one of coherent demodulation and non-coherent demodulation.

46. The apparatus as recited in claim 44, and further comprising:

means for receiving multiple bit streams from at least one of;

an associated multiple satellite vehicle (SV) transmitters, and/or an associated multiple sub-frames from one of said SV transmitters;

means for correlating said known and/or predicted bit sequence with each of said multiple bit streams at said multiple time-shifted hypotheses to provide an associated multiple correlation results for each time-shifted hypothesis;

for each time-shifted hypothesis, means for combining said associated multiple correlation results; and

means for identifying a bit position associated with each combined correlation result.

47. An apparatus comprising:

at least one processing unit to;

obtain a sequence of bits from a Satellite Positioning System (SPS) signal comprising one or more data sub-frames;

select a time-setting algorithm from among a plurality of time-setting algorithms based, at least in part, on a type of demodulation performed on said SPS signal;

correlate a known and/or predicted bit sequence with said received SPS signal at multiple time-shifted hypotheses;

verify a maximum peak in comparison with other peak information resulting from said correlating;

detect a sub-frame preamble in said received SPS signal based, at least in part, on results from said verified maximum peak; and

determine a SPS time based, at least in part, on a position of said detected sub-frame preamble in said sequence of bits, wherein said time-selecting algorithm affects said at least one processing unit in performing at least one of said correlation and/or said verification.

48. The apparatus as recited in claim 47, wherein said type of demodulation performed on said SPS signal comprises at least one of coherent demodulation and non-coherent demodulation.

49. The apparatus as recited in claim 47, said at least one processing unit to further:

obtain multiple bit streams from at least one of;

an associated multiple satellite vehicle (SV) transmitters, and/or an associated multiple sub-frames from one of said SV transmitters;

correlate said known and/or predicted bit sequence with each of said multiple bit streams at said multiple time-shifted hypotheses to provide an associated multiple correlation results for each time-shifted hypothesis;

for each time-shifted hypothesis, combine said associated multiple correlation results; and

identify a bit position associated with each combined correlation result.

50. An article comprising:

a non-transitory computer readable medium having stored therein computer-implementable instructions executable by one or more processing units to;

obtain a sequence of bits from a Satellite Positioning System (SPS) signal comprising one or more data sub-frames;

select a time-setting algorithm from among a plurality of time-setting algorithms based, at least in part, on a type of demodulation performed on said SPS signal;

correlate a known and/or predicted bit sequence with said received SPS signal at multiple time-shifted hypotheses;

verify a maximum peak in comparison with other peak information resulting from said correlating;

detect a sub-frame preamble in said received SPS signal based, at least in part, on results from said verified maximum peak; and

determine a SPS time based, at least in part, on a position of said detected sub-frame preamble in said sequence of bits,

wherein said time-selecting algorithm affects said one or more processing units in performing at least one of said correlation and/or said verification.

51. The article as recited in claim 50, wherein said type of demodulation performed on said SPS signal comprises at least one of coherent demodulation and non-coherent demodulation.

52. The article as recited in claim 50, said computer-implementable instructions being further executable by said one or more processing units to further:

obtain multiple bit streams from at least one of;

an associated multiple satellite vehicle (SV) transmitters, and/or an associated multiple sub-frames from one of said SV transmitters;

correlate said known and/or predicted bit sequence with each of said multiple bit streams at said multiple time-shifted hypotheses to provide an associated multiple correlation results for each time-shifted hypothesis;

for each time-shifted hypothesis, combine said associated multiple correlation results; and

identify a bit position associated with each combined correlation result.