Method and Apparatus for Processing of Satellite Signals Without Time of Day Information

• US 20080036651A1
• Filed: 07/09/2007
• Published: 02/14/2008
• Est. Priority Date: 11/17/2000
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Global Locate Incorporated (Broadcom, Inc.)
• Inventors: Abraham, Charles, van Diggelen, Frank
• Granted Patent: US 8,692,712 B2
• Time in Patent Office: Days
• US Class Current: 342/357.02
• CPC Class Codes: G01S 19/01 Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• 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
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0018 Transmission from mobile station to base station
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station

Abstract

Method and apparatus for locating position of a satellite signal receiver is described. In one example, pseudoranges are obtained that estimate the range of a satellite signal receiver to a plurality of satellites. An absolute time and a position are computed using the pseudoranges at a first time. The absolute time is then used to compute another position at a subsequent time. In another example, a plurality of states associated with a satellite signal receiver are estimated, where the plurality of states includes a time tag error state. A dynamic model is then formed relating the plurality of states, the dynamic model operative to compute position of the satellite signal receiver.

Claims

1. A method of locating position of a satellite signal receiver, comprising:

obtaining pseudoranges that estimate the range of the satellite signal receiver to a plurality of satellites;

computing an absolute time and a position using the pseudoranges at a first time;

using the absolute time to compute another position at a subsequent time.

2. The method of claim 1, wherein the computing comprises:

obtaining a-priori estimates of time and position; and

calculating the position and the absolute time of reception using a mathematical model that updates the a-priori estimates of time and position.

3. The method of claim 1, wherein the absolute time is used to compute the other position in response to the absolute time being computed to a predefined accuracy.

4. The method of claim 3, further comprising:

deriving the predefined accuracy from at least one of the number of the pseudoranges obtained, a dilution or precision value related to the plurality of satellite signals, signal-to-noise ratios of the plurality of satellite signals, and a-posteriori pseudorange residuals.

5. The method of claim 1, further comprising:

computing a plurality of time tag errors using the pseudoranges at a respective plurality of times between the first time and the subsequent time; and

averaging the plurality of time tag errors to produce the absolute time.

6. The method of claim 1, wherein the other position is computed using a standard global positioning system calculation, and wherein the absolute time is used as a known value in the standard global positioning system calculation.

7. The method of claim 1, wherein the other position is computed using a mathematical model that updates a-priori estimates of time and position, and wherein the absolute time is used as an additional measurement in the mathematical model.

8. The method of claim 1, further comprising:

sending the pseudoranges to a server using a wireless communication system, wherein the absolute time, the position, and the other position are computed using the server.

9. The method of claim 1, wherein the absolute time, the position, and the other position are computed within the satellite signal receiver.

10. A method, comprising:

estimating a plurality of states associated with a satellite signal receiver, the plurality of states including a time tag error state; and

forming a dynamic model relating the plurality of states, the dynamic model operative to compute position of the satellite signal receiver.

11. The method of claim 10, wherein the plurality of states further include a state related to a common mode error and at least one state related to the position of the satellite signal receiver

12. The method of claim 10, further comprising:

obtaining pseudoranges that estimate the range of the satellite signal receiver to a plurality of satellites;

updating the plurality of states within the dynamic model using the pseudoranges; and

computing a position of the satellite signal receiver using the dynamic model.

13. The method of claim 10 wherein the dynamic model is formed within a sequential estimator.

14. The method of claim 10, further comprising:

obtaining time-of-week information;

estimating a known value for the time tag error state within the dynamic model using the time-of-week information.

15. The method of claim 14, further comprising:

decoding the time-of-week information from ephemeris data transmitted by a plurality of satellites.

16. The method of claim 10, further comprising:

obtaining time-of-week information;

removing the time tag error state from the dynamic model in response to the time-of-week information.

17. The method of claim 16, further comprising:

decoding the time-of-week information from ephemeris data transmitted by a plurality of satellites.

18. A system for computing position of a satellite signal receiver, comprising:

a mobile device comprising a satellite signal receiver and a wireless transceiver;

a server being in wireless communication with the mobile device, where the satellite signal receiver provides pseudoranges that estimate the range of the satellite signal receiver to a plurality of satellites, and the wireless transceiver transmits the pseudoranges to the server, and where the server computes an absolute time and a position of the satellite signal receiver using the pseudoranges at a first time, and uses the absolute time to compute another position of the satellite signal receiver at a subsequent time.

19. A system, comprising:

a mobile device comprising a satellite signal receiver and a wireless transceiver;

a server being in wireless communication with the mobile device, where the satellite signal receiver provides pseudoranges that estimate the range of the satellite signal receiver to a plurality of satellites, and the wireless transceiver transmits the pseudoranges to the server, and where the server includes a sequential estimator having a plurality of states associated with a satellite signal receiver, the plurality of states including a time tag error state.

20. The system of claim 19, wherein the sequential estimator is a Kalman filter.

21. A mobile device, comprising:

a satellite signal receiver for providing pseudoranges that estimate the range of the mobile device to a plurality of satellites; and

a sequential estimator having a plurality of states associated with the satellite signal receiver, the plurality of states including a time tag error state.

22. The mobile device of claim 21, wherein the sequential estimator is a Kalman filter.