Method and apparatus for managing time in a satellite positioning system

• US 7,327,310 B2
• Filed: 10/28/2004
• Issued: 02/05/2008
• Est. Priority Date: 11/07/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Global Locate Incorporated (Broadcom, Inc.)
• Inventors: Abraham, Charles, De Salas, Javier, McMahan, David
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US10/976,191
• Publication Number:
  US 20050146462A1
• Time in Patent Office: 1,195 Days
• Field of Search: 342/357.01, 342/357.02, 342/357.06, 342/357.12, 701/207, 701/213, 701/215
• US Class Current: 342/357.62
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• 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 time management in a position location system is described. In one example, a time relation is received at a server. The time relation includes a relationship between an air-interface time of a base station and a satellite time for a satellite constellation from a first satellite positioning system (SPS) receiver. The time relation is then stored in the server. In another example, satellite time is determined at a first time for a satellite constellation at an SPS receiver. A time offset is determined between the satellite time and an air-interface time of a base station. The time offset is stored within the SPS receiver. A position of the SPS receiver is computed at a second time using satellite measurements and the stored time offset.

Claims

1. A method, comprising:

determining satellite time for a satellite constellation using a first mobile satellite positioning system (SPS) receiver, wherein said first mobile SPS receiver is operable to receive service via said base station;

producing, at said mobile SPS receiver, a time relation between said satellite time, an air-interface time of a base station and a propagation-delay time, wherein said propagation-delay time comprises at least one of a timing advance and a round trip time; and

sending said time relation from said first mobile SPS receiver to one of a server and a memory in said SPS receiver.

2. The method of claim 1, further comprising:

computing a time offset between said satellite time and said air-interface time from said time relation at said server.

3. The method of claim 2, wherein said time relation comprises an association between said satellite time and a frame number.

4. The method of claim 1, wherein said time relation comprises a time offset between said satellite time and said air-interface time.

5. The method of claim 1, further comprising:

compensating said time relation for a propagation delay between said base station and said first mobile SPS receiver.

6. The method of claim 5, wherein said step of compensating comprises:

sending a value indicative of a timing advance from said first mobile SPS receiver to said server.

7. The method of claim 5, wherein said step of compensating comprises:

appending a value indicative of a timing advance to said time relation at said base station.

8. The method of claim 1, further comprising:

obtaining satellite measurements at a second SPS receiver;

time stamping said satellite measurements using said air-interface time;

sending said time stamped satellite measurements to said server;

computing position of said second SPS receiver using said time stamped satellite measurements and said time relation.

9. The method of claim 1, further comprising:

obtaining satellite measurements at a second SPS receiver;

time stamping said satellite measurements using said air-interface time;

obtaining data indicative of said time relation at said second SPS receiver from said server; and

computing position of said second SPS receiver using said time stamped satellite measurements and said data.

10. The method of claim 9, wherein said data comprises a value associated with said satellite time and a frame number.

11. The method of claim 1, wherein said step of determining said satellite time comprises:

processing satellite signals in said first mobile SPS receiver to decode a time value.

12. The method of claim 1, wherein said step of determining said satellite time comprises:

obtaining satellite measurements, a position estimate, a time estimate, and satellite trajectory data at said first mobile SPS receiver; and

relating said satellite measurements, said position estimate, said time estimate, and said satellite trajectory data using a mathematical model to compute a time value.

13. A method, comprising:

determining, at a mobile satellite positioning system (SPS) receiver at a first time, a satellite time for a satellite constellation, wherein said mobile SPS receiver is operable to receive service via a base station;

determining a time offset from said satellite time as a function of an air-interface time of said base station and a propagation-delay time, wherein said propagation-delay time comprises at least one of a timing advance and a round trip time;

storing said time offset; and

computing, at a second time, a position of said mobile SPS receiver using satellite measurements and said stored time offset.

14. The method of claim 13, wherein said step of computing comprises:

synchronizing clock circuitry in said mobile SPS receiver to said air-interface time; and

compensating said clock circuitry using said time offset.

15. The method of claim 13, further comprising:

deactivating said mobile SPS receiver in response to storage of said time offset; and

activating said mobile SPS receiver prior to computing said position.

16. The method of claim 13, wherein said step of determining said satellite time comprises:

processing satellite signals in said mobile SPS receiver to decode a time value.

17. The method of claim 13, wherein said step of determining said satellite time comprises:

obtaining initial satellite measurements, a position estimate, a time estimate, and satellite trajectory data at said mobile SPS receiver; and

relating said initial satellite measurements, said position estimate, said time estimate, and said satellite trajectory data using a mathematical model to compute a time value.

18. A method, comprising:

determining, at a mobile satellite positioning system (SPS) receiver at a first time, a satellite time for a satellite constellation, wherein said mobile SPS receiver is operable to receive service via a base station;

determining a time offset from said satellite time as a function of an air-interface time of said base station and a propagation-delay time, wherein said propagation-delay time comprises at least one of a timing advance and a round trip time;

storing said time offset;

synchronizing, at a second time, clock circuitry in said mobile SPS receiver to said satellite time using said time offset in response to a handover from said base station to another base station; and

determining another time offset between said satellite time and another air-interface time of said other base station using said synchronized clock circuitry.

19. A position location system, comprising:

a base station having an air-interface time associated therewith;

a mobile satellite positioning system (SPS) receiver operable to receive service from said base station, wherein said mobile SPS receiver is operable to determine satellite time for a satellite constellation and produce a time relation as a function of said satellite time, air-interface time and a propagation-delay time, wherein said propagation-delay time comprises at least one of a timing advance and a round trip time; and

a server for receiving said time relation from said mobile SPS receiver.