METHOD AND APPARATUS FOR MANAGING TIME IN A SATELLITE POSITIONING SYSTEM

• US 20090146871A1
• Filed: 12/07/2007
• Published: 06/11/2009
• Est. Priority Date: 12/07/2007
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: McMahan, David, Abraham, Charles, De Salas, Javier
• Application Number:
  US11/952,803
• Publication Number:
  US 20090146871A1
• Time in Patent Office: Days
• US Class Current: 342/357.730
• 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

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:

receiving, at a server, a time relation 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; and

storing said time relation in said server.

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, wherein said time relation includes compensation for a propagation delay between said first SPS receiver and said base station.

6. The method of claim 1, further comprising:

receiving, at said server, satellite measurements from a second SPS receiver, said satellite measurements being time stamped using said air-interface time; and

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

7. The method of claim 1, further comprising:

receiving a request for said time relation from a second SPS receiver; and

sending data indicative of said time relation to said second SPS receiver in response to said request.

8. The method of claim 7, wherein said data comprises a value associated with said satellite time and a frame number.

9. The method of claim 1, further comprising:

receiving, at said server, at least one additional time relation between an air-interface time of at least one additional base station and said satellite time; and

storing said at least one additional time relation along with said relation to produce a set of time relations.

10. The method of claim 9, further comprising:

receiving, at said server, satellite measurements from a second SPS receiver, said satellite measurements being time stamped using an air-interface time of a second base station;

identifying a corresponding time relation for said second base station in said set of time relations; and

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

11. A method, comprising:

determining satellite time for a satellite constellation using a first satellite positioning system (SPS) receiver;

producing a time relation between said satellite time and an air-interface time of a base station;

sending said time relation from said first SPS receiver to a server.

12. The method of claim 11, further comprising:

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

13. The method of claim 12, wherein said time relation comprises an association between said satellite time and a frame number.

14. The method of claim 11, wherein said time relation comprises a time offset between said satellite time and said air-interface time.

15. The method of claim 11, further comprising:

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

16. The method of claim 15, wherein said step of compensating comprises:

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

17. The method of claim 15, wherein said step of compensating comprises:

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

18. The method of claim 11, 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.

19. The method of claim 11, 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.

20. The method of claim 19, wherein said data comprises a value associated with said satellite time and a frame number.

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

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

22. The method of claim 11, 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 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.

23. A method, comprising:

determining, at a first time, a satellite time for a satellite constellation at a satellite positioning system (SPS) receiver;

determining a time offset between said satellite time and an air-interface time of a base station;

storing said time offset;

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

24. The method of claim 23, wherein said step of computing comprises:

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

compensating said clock circuitry using said time offset.

25. The method of claim 23, further comprising:

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

activating said SPS receiver prior to computing said position.

26. The method of claim 23, wherein said step of determining said satellite time comprises:

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

27. The method of claim 23, 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 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.

28. A method, comprising:

determining, at a first time, a satellite time for a satellite constellation at a satellite positioning system (SPS) receiver;

determining a time offset between said satellite time and an air-interface time of a base station;

storing said time offset;

synchronizing, at a second time, clock circuitry in said 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.

29. A position location server, comprising:

an interface for receiving a time relation 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; and

a storage device for storing said time relation.

30. A position location system, comprising:

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

a first satellite positioning system (SPS) receiver for determining satellite time for a satellite constellation and producing a time relation between said satellite time and said air-interface time; and

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