Ephemeris extension method for GNSS applications

• US 9,000,979 B2
• Filed: 09/27/2011
• Issued: 04/07/2015
• Est. Priority Date: 04/24/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Garin, Lionel
• Primary Examiner(s): Issing, Gregory C
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US13/246,727
• Publication Number:
  US 20120256792A1
• Time in Patent Office: 1,288 Days
• Field of Search: 342/357.66, 342/357.42, 342/357.64
• US Class Current: 342/357.64
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver

Abstract

Systems, methods and devices for improving the performance of Global Navigation Satellite System (GNSS) receivers are disclosed. In particular, the improvement of the ability to calculate a satellite position or a receiver position where a receiver has degraded ability to receive broadcast ephemeris data directly from a GNSS satellite is disclosed. Correction terms can be applied to an approximate long-term satellite position model such as the broadcast almanac.

Claims

1. A method comprising:

storing in a memory of a receiver, a prediction file comprising satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites, the satellite position prediction data comprising, for each respective satellite and a plurality of time intervals, a separate set of data corresponding to a predicted position of the respective satellite at each time interval;

defining, by a processor, at least one separate correction value for each respective satellite, the at least one correction value being valid for use during at least one of the time intervals, the at least one separate correction value is weighted based, at least in part, on the time interval for which the at least one separate correction value is defined;

storing in the prediction file, the at least one separate correction value for each respective satellite, in association with the separate set of data in the prediction file corresponding to the predicted position of the respective satellite;

calculating, by the processor, at least one corrected satellite position of a respective one of the satellites at said at least one defined time interval by applying the correction value that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites; and

estimating, by the processor, a position of the receiver based, at least in part on said at least one corrected satellite position.

2. The method of claim 1, wherein said satellite position prediction data comprises almanac data.

3. The method of claim 1, wherein defining, by the processor, at least one correction value for each satellite comprises defining at least one separate correction value for each separate satellite, for each separate one of the plurality of time intervals.

4. The method of claim 1, wherein defining, by the processor, at least one correction value for each satellite comprises defining at least one separate correction value for each separate one of the plurality of time intervals.

5. The method of claim 1, wherein said satellite position prediction data for each of said time intervals is based, at least in part, on a model comprising Kepler almanac parameters.

6. The method of claim 1, wherein said satellite position prediction data comprises Kepler almanac parameters and wherein said at least one correction value comprises a plurality of correction factors associated with the Kepler almanac parameters.

7. The method of claim 6, wherein said correction factors comprise at least one of harmonic correction factors or polynomial correction factors.

8. The method of claim 1, further comprising:

receiving, at the receiver, the prediction file over a secure user plane for location (SUPL) network.

9. The method of claim 1, further comprising:

receiving, at the receiver, the prediction file during synchronization for a personal digital assistant that contains the receiver.

10. The method of claim 1, further comprising:

receiving, at the receiver, the prediction file during an Assisted Global Positioning System (A-GPS) session.

11. The method of claim 1 further comprising storing, by the processor, the prediction file in the memory of the receiver before calculating the at least one corrected satellite position.

12. The method of claim 1, wherein the at least one correction value for each respective satellite comprises at least one different correction value for each one of a plurality of different time intervals.

13. The method of claim 1, wherein the at least one separate correction value is calculated by computing a difference between the satellite position prediction data and a second prediction data using a least squares methodology.

14. The method of claim 13, wherein the at least one separate correction value is weighted by weighting the second prediction data based, at least in part, on a time period for which the second prediction data is defined.

15. The method of claim 14, wherein

a first set of the second prediction data is defined for a first time period;

a second set of the second prediction data is defined for a second time period later in time than the first time period; and

the weighting of the second prediction data comprises weighting the first set of the second prediction data more than the second set of the second prediction data.

16. The method of claim 1, wherein a first correction value of the at least one separate correction value is defined at a first time interval, a second correction value of the at least one separate correction value is defined at a second time interval, the first time interval is earlier in time than the second time interval, and the first correction value is weighted more than the second correction value.

17. The method of claim 1, wherein calculating, by the processor, the at least one corrected satellite position comprising applying the weighted correction value that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites.

18. A method of estimating a position of a receiver, the method comprising:

storing in memory associated with the receiver a prediction file comprising a plurality of almanac correction data sets valid for use during a corresponding plurality of respective, defined time intervals, the prediction file further comprising, for each of a plurality of respective satellites, a separate set of data corresponding to a predicted position of the respective satellite at each defined time interval;

calculating, by a processor, at least one corrected satellite position of one of the satellites at one of said defined time intervals by applying the correction data stored in the prediction file that is valid for use during said one of said defined time intervals to correct the separate set of data corresponding to the predicted position of the satellite, the correction data is weighted based, at least in part, on said one of said defined time intervals for which the correction data is defined; and

estimating, by the processor, a position of the receiver based, at least in part on said at least one corrected satellite position.

19. The method of claim 18, wherein said almanac correction data includes different sets of correction data in at least two of the plurality of defined time intervals.

20. A method comprising creating and storing, by a processor, a prediction file comprising, for each one of a plurality of respective satellites, a set of satellite position data corresponding to a predicted position of the respective satellite at each one of a plurality of defined time intervals, and almanac correction data associated in the prediction file with each set of satellite position data, said almanac correction data being based, at least in part, on a first prediction of a satellite orbit and a second prediction of said satellite orbit, and the almanac correction data is weighted based, at least in part, on a time for which the almanac correction data is defined.

21. The method of claim 20, wherein the almanac correction data comprising at least one different correction value for each of the plurality of defined time intervals.

22. The method of claim 20, wherein said almanac correction data comprises at least one of coordinate correction data or coordinate derivative correction data associated with said at least one of said plurality of defined time intervals.

23. The method of claim 20, wherein said almanac correction data for at least one of said plurality of defined time intervals is based, at least in part, on a model comprising Kepler almanac parameters.

24. The method of claim 20, wherein said almanac correction data comprises Kepler almanac parameters and correction factors.

25. The method of claim 24, wherein said correction factors comprise at least one of harmonic correction factors or polynomial correction factors.

26. A Global Navigational Satellite System (GNSS) receiver comprising:

a memory configured to store a prediction file comprising satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites, the satellite position prediction data comprising, for each respective satellite and a plurality of time intervals, a separate set of data corresponding to a predicted position of the respective satellite at each time interval;

a processor configured to define at least one separate correction value for each respective satellite, the at least one separate correction value being valid for use during at least one of the time intervals, the at least one separate correction value is weighted based, at least in part, on the time interval for which the at least one separate correction value is defined;

the at least one separate correction value for each respective satellite being associated in the prediction file with the separate set of data in the prediction file corresponding to the predicted position of the respective satellite;

the processor further configured to calculate at least one corrected satellite position of a respective one of the satellites at said at least one defined-time interval by applying the correction value that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites; and

the processor further configured to estimate estimating a position of the receiver based, at least in part on said at least one corrected satellite position.

27. The receiver of claim 26, wherein said satellite position prediction data comprises almanac data.

28. The receiver of claim 26, wherein the processor is configured to define at least one separate correction value for each separate satellite, for each separate one of the plurality of time intervals.

29. The receiver of claim 28, wherein said satellite position prediction data for at least one of said plurality of defined time intervals is based, at least in part, on a model comprising Kepler almanac parameters and associated correction factors.

30. The receiver of claim 29, wherein said correction factors comprise at least one of harmonic correction factors or polynomial correction factors.

31. The receiver of claim 26, wherein said satellite position prediction data comprises Kepler almanac parameters and wherein said at least one correction value comprises a plurality of correction factors associated with the Kepler almanac parameters.

32. A device comprising:

a memory configured to store a prediction file;

at least one processor configured to;

obtain the prediction file comprising satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites, the satellite position prediction data comprising, for each respective satellite and a plurality of time intervals, a separate set of data corresponding to a predicted position of the respective satellite at each time interval;

obtain at least one separate correction value for each respective satellite, the at least one separate correction value being valid for use during at least one of the time intervals,

the at least one separate correction value for each respective satellite being associated in the prediction file with the separate set of data in the prediction file corresponding to the predicted position of the respective satellite, the at least one separate correction value is weighted based, at least in part, on the at least one time interval for which the at least one separate correction value is defined;

calculate at least one corrected satellite position of a respective one of the satellites at said at least one defined time interval by applying the correction value that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites; and

estimate a position of the receiver based, at least in part on said at least one corrected satellite position.

33. An article comprising:

a non-transitory computer readable medium having computer code stored therein that is implementable by a processor of a receiver to;

obtain a prediction file comprising satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites, the satellite position prediction data comprising, for each respective satellite and a plurality of time intervals, a separate set of data corresponding to a predicted position of the respective satellite at each time interval;

obtain at least one separate correction value for each respective satellite, the at least one separate correction value being valid for use during at least one of the time intervals,

the at least one separate correction value for each respective satellite being associated in the prediction file with the separate set of data in the prediction file corresponding to the predicted position of the respective satellite, wherein the at least one separate correction value is weighted based, at least in part, on the at least one time interval for which the at least one separate correction value is defined;

calculate at least one corrected satellite position of a respective one of the satellites at said at least one defined time interval by applying the correction value that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites; and

estimate a position of the receiver based, at least in part on said at least one corrected satellite position.

34. A device comprising:

means, in a receiver, for storing a prediction file comprising satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites, the satellite position prediction data comprising, for each respective satellite and a plurality of time intervals, a separate set of data corresponding to a predicted position of the respective satellite at each time interval; and

processing means for defining at least one separate correction value for each respective satellite, the at least one correction value being valid for use during at least one of the time intervals, the at least one separate correction value is weighted based, at least in part, on the at least one time interval for which the at least one separate correction value is defined;

the at least one separate correction value for each respective satellite being associated in the prediction file with the separate set of data in the prediction file corresponding to the predicted position of the respective satellite;

the processing means for calculating at least one corrected satellite position of a respective one of the satellites at said at least one defined time interval by applying the correction value that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites; and

the processing means for estimating a position of the receiver based, at least in part on said at least one corrected satellite position.

35. The device of claim 34, wherein the at least one correction value comprising at least one different correction value for each different one of the plurality of defined time intervals.

36. The device of claim 35, wherein said satellite position prediction data for at least one of said plurality of defined time intervals is based, at least in part, on a model comprising Kepler almanac parameters and associated correction factors.

37. The device of claim 36, wherein said correction factors comprise at least one of harmonic correction factors or polynomial correction factors.

38. The device of claim 34, wherein the processing means comprises means for defining at least one separate correction value for each separate satellite, for each separate one of the plurality of separate time intervals.

39. A receiver comprising:

at least one memory configured to store a prediction file comprising a plurality of almanac correction data sets valid for use during a corresponding plurality of respective, defined time intervals, the prediction file further comprising satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites, the satellite position prediction data comprising, for each respective satellite and each one of the defined time intervals, a separate set of data corresponding to a predicted position of the respective satellite at the defined time interval;

at least one processor configured to calculate at least one corrected satellite position of a respective one of the satellites at one of said defined time intervals by applying the correction data stored in the prediction file that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites and the defined time interval, the correction data is weighted based, at least in part, on the defined time interval for which the correction data is defined; and

the at least one processor configured to estimate a position of the receiver based, at least in part on said at least one corrected satellite position.

40. The receiver of claim 39, wherein said almanac correction data includes different sets of correction data in at least two of the plurality of defined time intervals.

41. An article comprising:

a non-transitory computer readable medium having computer code stored therein that is implementable by a processor of a receiver to;

obtain from at least one memory of a receiver, contents of a prediction file comprising a plurality of almanac correction data sets valid for use during a corresponding plurality of respective, defined time intervals, the prediction file further comprising satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites, the satellite position prediction data comprising, for each respective satellite and each one of the defined time intervals, a separate set of data corresponding to a predicted position of the respective satellite at the defined time interval, wherein each of the plurality of almanac correction data sets is weighted based, at least in part, on each of the a corresponding plurality of respective, defined time intervals for which the each of the plurality of almanac correction data sets is defined;

calculate at least one corrected satellite position of a respective one of the satellites at one of said defined time intervals by applying the correction data stored in the prediction file that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites and the defined time interval; and

estimate a position of the receiver based, at least in part on said at least one corrected satellite position.

42. The article of claim 41, wherein said almanac correction data includes different sets of correction data in at least two of the plurality of defined time intervals.

43. A device comprising:

means, in a receiver, for storing a prediction file comprising a plurality of almanac correction data sets valid for use during a corresponding plurality of respective, defined time intervals, the prediction file further comprising satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites, the satellite position prediction data comprising, for each respective satellite and each one of the defined time intervals, a separate set of data corresponding to a predicted position of the respective satellite at the defined time interval; and

processing means for calculating at least one corrected satellite position of a respective one of the satellites at one of said defined time intervals by applying the correction data stored in the prediction file that is associated with the separate set of data corresponding to the predicted position for the respective one of the satellites and the defined time interval, the correction data is weighted based, at least in part, on the defined time interval for which the correction data is defined; and

the processing means for estimating a position of the receiver based, at least in part on said at least one corrected satellite position.

44. A receiver comprising a processor configured to create and store a prediction file comprising, for each one of a plurality of respective satellites, a set of satellite position data corresponding to a predicted position of the respective satellite at each one of a plurality of defined time intervals, and almanac correction data associated in the prediction file with each set of satellite position data, said almanac correction data being based, at least in part, on a first prediction of a satellite orbit and a second prediction of said satellite orbit, and the almanac correction data is weighted based, at least in part, on a time interval for which the almanac correction data is defined.

45. The receiver of claim 44, wherein the almanac correction data comprising at least one different correction value for each of the plurality of defined time intervals.

46. The receiver of claim 45, wherein said almanac correction data comprises at least one of coordinate correction data or coordinate derivative correction data associated with said at least one of said plurality of defined time intervals.

47. The receiver of claim 45, wherein said almanac correction data for at least one of said plurality of defined time intervals is based, at least in part, on a model comprising Kepler almanac parameters.

48. An article comprising:

a non-transitory computer readable medium having computer code stored therein that is implementable by a processor of a receiver to create and store a prediction file comprising, for each one of a plurality of respective satellites, a set of satellite position data corresponding to a predicted position of the respective satellite at each one of a plurality of defined time intervals, and almanac correction data associated in the prediction file with each set of satellite position data, said almanac correction data being based, at least in part, on a first prediction of a satellite orbit and a second prediction of said satellite orbit, the almanac correction data is weighted based, at least in part, on a time interval for which the almanac correction data is defined.

49. A method comprising:

storing, in a memory of a receiver, a prediction file comprising (a) satellite position prediction data associated with a plurality of satellites for defining predicted positions of each of the satellites over a plurality of defined time intervals and (b) at least one correction value for each satellite, the at least one correction value being valid for use during at least one of the defined time intervals;

calculating, by a processor, at least one corrected satellite position at said at least one defined time interval by applying the correction value that is valid for use during said at least one defined time interval to the satellite position prediction data associated with said at least one defined time interval, and the correction value is weighted based, at least in part, on said at least one defined time interval for which the correction value is defined; and

estimating, by the processor, a position of the receiver based, at least in part on said at least one corrected satellite position.