Method and apparatus for locating position of a GPS device

1. A method for provisioning a mobile device with a model for determining a position of the mobile device in at least one geographic area, the method comprising:

forming, by a processor, at least one satellite orbit model and a wide area model formed from measurements from a plurality of satellites of a Global Positioning System, and wherein said at least one satellite orbit model is formed based on measurements obtained by a plurality of reference stations, and wherein the wide area model comprises satellite clocks from said plurality of satellites of the Global Positioning System; and

sending, by the processor, the at least one satellite orbit model to the mobile device.

2. The method of claim 1 , wherein forming the at least one satellite orbit model comprises:

forming a pseudorange model as a function of an estimate of the position of the mobile device and the wide area model.

3. The method of claim 1 , wherein forming the at least one satellite orbit model comprises:

forming a pseudorange model as a function of an estimate of the position of the mobile device and the wide area model; and

forming information representing differences between an almanac stored in a memory of the mobile device and the pseudorange model.

4. The method of claim 1 , wherein forming the at least one satellite orbit model comprises:

forming a compact orbit model as a function of an estimate of the position of the mobile device and the wide area model.

5. The method of claim 1 , wherein sending the at least one satellite orbit model to the mobile device occurs responsive to receiving a request for the position of the mobile device.

6. The method of claim 5 , wherein receiving the request for the position of the mobile device comprises:

receiving the request for the position of the mobile device from the mobile device.

7. The method of claim 1 , further comprising obtaining an estimate of the position of the mobile device, obtaining the estimate of the position of the mobile device, comprises:

deriving the estimate from a location of a base station of a network to which the mobile device communicated.

8. The method of claim 1 , further comprising obtaining an estimate of the position of the mobile device, wherein obtaining the estimate of the position of the mobile device, comprises:

deriving the estimate from a registration of the mobile device in a market service area; and

packetizing the estimate in a packet containing a pseudorange measurement.

9. The method of claim 1 , wherein the measurements obtained by the plurality of reference stations include measurements with respect to respective positions of said plurality of reference stations.

10. The method of claim 1 , wherein the measurements obtained by the plurality of reference stations are measured by the plurality of reference stations.

11. The method of claim 1 , wherein each of the plurality of reference stations obtains measurements from at least one common satellite.

12. The method of claim 11 , where each of the plurality of reference stations directly obtains measurements from at least one common satellite.

13. A method for provisioning a mobile device with a model for determining a position of the mobile device in at least one geographic area, the method comprising:

receiving by the mobile device from a server at least one satellite orbit model, wherein the at least one satellite orbit model is formed from an estimate of a position of the mobile device, and wherein the at least one satellite orbit models is formed from measurements obtained by a plurality of reference stations.

14. The method of claim 13 , further comprising: processing elements operable to determine the estimate of the position of the mobile device as a function of a positioning signal.

15. The method of claim 13 , further comprising:

receiving at the mobile device a request for obtaining the position of the mobile device, and

sending the request from the mobile device to the server.

16. The method of claim 13 , wherein the at least one satellite orbit model comprises a pseudorange model.

17. The method of claim 13 , wherein the at least one satellite orbit model comprises a compact orbit model.

18. The method of claim 17 , wherein the compact orbit model includes information that enables the mobile device to compute the position.

19. The method of claim 17 , wherein receiving the at least one satellite orbit model comprises receiving the at least one satellite orbit model via a broadcast.

20. The method of claim 13 , wherein the at least one satellite orbit model comprises: information representing differences between an almanac stored in a memory of the mobile device and a pseudorange model, and wherein the pseudorange model is formed as a function of the estimate of the position of the mobile device and the wide area model.

21. The method of claim 20 , wherein the information is adjusted for a timing of a clock of the mobile device.

22. A system for provisioning a mobile device with a model for determining a position of the mobile device in at least one geographic area, the system comprising:

a first device for obtaining an estimate of the position of the mobile device;

a server for forming at least one satellite orbit model from the estimate of the position of the mobile device and a wide area model formed from measurements from a plurality of satellites of a Global Positioning System, wherein said at least one satellite orbit model is formed from measurements obtained by a plurality of reference stations, and for sending the at least one satellite orbit model to the mobile device, wherein the wide area model comprises tropospheric delays for said plurality of satellites of the Global Positioning System.

23. The system of claim 22 , wherein the first device comprises the server.

24. The system of claim 22 , wherein the first device comprises the mobile device, wherein the mobile device is operable to send the estimate to the server.