METHOD AND APPARATUS FOR POSITION DETERMINATION WITH EXTENDED SPS ORBIT INFORMATION

• US 20090315772A1
• Filed: 02/05/2009
• Published: 12/24/2009
• Est. Priority Date: 11/10/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Moegiein, Mark Leo, Biacs, Zoltan F., Sheynblat, Leonid, Gum, Arnold Jason, Wengler, Michael James
• Granted Patent: US 8,319,684 B2
• Time in Patent Office: Days
• US Class Current: 342/357.290
• CPC Class Codes: G01S 19/05 providing aiding data
• 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

A method and system for assisting mobile stations to locate a satellite use an efficient messaging format. A server computes a correction between coarse orbit data of a satellite and precise orbit data of the satellite. A coordinate system is chosen such that variation of the correction is substantially smooth over time. The server further approximates the correction with mathematical functions to reduce the number of bits necessary for transmission to a mobile station. The mobile station, upon receiving the coefficients, evaluates the mathematical functions using the coefficients and a time of applicability (e.g., the current time), converts the evaluated result to a standard coordinate system, and applies the conversion result to the coarse orbit data to obtain the precise orbit data.

Claims

1. A method of a mobile station, comprising:

receiving real-time orbit data of a first satellite; and

combining the real-time orbit data of the first satellite and predicted orbit data of a second satellite in determination of spatial and time information of the mobile station.

2. The method of claim 1, wherein the predicted orbit data is at least in part approximated by corrected orbital data.

3. The method of claim 1, wherein the predicted orbit data comprises coarse orbit data and orbital corrections.

4. The method of claim 1, further comprising:

using the real-time orbit data of the first satellite in an earlier time period to correct an error of a clock bias in predicted orbit data of the first satellite in a later time period.

5. The method of claim 1, further comprising:

switching from the predicted orbit data of the second satellite to real-time orbit data of the second satellite when the real-time orbit data of the second satellite becomes available; and

using the real-time orbit data of the second satellite in the determination of the spatial and time information of the mobile station.

6. The method of claim 1, further comprising:

switching from the real-time orbit data of the first satellite to predicted orbit data of the first satellite when the real-time orbit data of the first satellite becomes unavailable; and

using the predicted orbit data of the first satellite in the determination of the spatial and time information of the mobile station.

7. The method of claim 6, further comprising:

interpolating the real-time data of the first satellite and the predicted orbit data of the first satellite to smooth a transition between the real-time data and the predicted orbit data by adjusting the predicted orbit data

8. The method of claim 6, further comprising:

monitoring an age of the real-time orbit data of the first satellite;

the age indicated by a time to Time of Ephemeris (TOE); and

switching from the real-time orbit data of the first satellite to the predicted orbit data of the first satellite when the age of the real-time orbit data exceeds a predetermined threshold.

9. A method of a mobile station, comprising:

receiving real-time orbit data from a plurality of satellites for a determination of spatial and time information of the mobile station; and

using the real-time orbit data of the plurality of satellites to correct an error of a clock bias in predicted orbit data of one or more additional satellites, wherein the number of satellites in the plurality of satellites is equal to or greater than the number of unknowns in the spatial and time information of the mobile station.

10. The method of claim 9, further comprising:

using the real-time orbit data of a first satellite in the plurality of satellites to correct the error of the clock bias in the predicted orbit data of the first satellite.

11. The method of claim 9, further comprising:

correcting the error of the clock bias in predicted orbit data using an estimation method.

12. The method of claim 9, wherein the estimation method includes a linear, linearized, or non-linear estimation method.

13. The method of claim 9, wherein the estimation method includes a Kalman filter or weighted least squares.

14. A system of a mobile station, comprising:

a receiver interface to receive real-time orbit data of a first satellite; and

a combining unit to combine the real-time orbit data of the first satellite with predicted orbit data of a second satellite in determination of spatial and time information of the mobile station.

15. The system of claim 14, wherein the combining unit is to use real-time orbit data of a third satellite, in place of the predicted orbit data of the second satellite, in the determination of the spatial and time information of the mobile station when the real-time orbit data of the third satellite becomes available.

16. The system of claim 14, wherein the combining unit is to use predicted orbit data of the first satellite, in place of the real-time orbit data of the first satellite, in the determination of the spatial and time information of the mobile station when the real-time orbit data of the first satellite becomes unavailable.

17. A mobile station, comprising:

means for receiving real-time orbit data of a first satellite; and

means for combining the real-time orbit data of the first satellite and predicted orbit data of a second satellite in determination of spatial and time information of the mobile station.

18. The mobile station of claim 17, further comprising:

means for switching from the predicted orbit data of the second satellite to real-time orbit data of the second satellite when the real-time orbit data of the second satellite becomes available; and

means for using the real-time orbit data of the second satellite in the determination of the spatial and time information of the mobile station.

19. The mobile station of claim 17, further comprising:

means for switching from the real-time orbit data of the first satellite to predicted orbit data of the first satellite when the real-time orbit data of the first satellite becomes unavailable; and

means for using the predicted orbit data of the first satellite in the determination of the spatial and time information of the mobile station.

20. A mobile station, comprising:

means for receiving real-time orbit data from a plurality of satellites for a determination of spatial and time information of the mobile station; and

means for using the real-time orbit data of the plurality of satellites to correct an error of a clock bias in predicted orbit data of one or more additional satellites, wherein the number of satellites in the plurality of satellites is equal to or greater than the number of unknowns in the spatial and time information of the mobile station.

21. A computer program product for enabling a computer to determine spatial and time information:

software instructions for enabling the computer to perform predetermined operations; and

a computer readable storage medium bearing the software instructions;

the predetermined operations including;

receiving information indicative of real-time orbit data of a first satellite; and

receiving information indicative of a combination of the real-time orbit data of the first satellite and predicted orbit data of a second satellite.

22. The computer program product of claim 21, wherein the predetermined operations are further adapted to correct an error of a clock bias in the predicted orbit data of the first satellite in a later time period using the real-time orbit data of the first satellite in an earlier time period.