Method and apparatus for locating a mobile receiver having a position cache

• US 20040203915A1
• Filed: 01/22/2003
• Published: 10/14/2004
• Est. Priority Date: 01/22/2003
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Abraham, Charles, van Diggelen, Frank
• Application Number:
  US10/349,493
• Publication Number:
  US 20040203915A1
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance 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 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and apparatus that uses a position cache for locating a position of an A-GPS receiver that is embedded in a mobile device. In one embodiment of the invention, the position cache is a look up table comprising cell identification codes and position information. The position information is generally the location of the center of each cell that is identified by a cell identification code in the table. This position information is used as a position estimate for the A-GPS receiver. The method receives a cell identification code from a wireless network, retrieves a position estimate from the a position cache that corresponds to the received cell identification code, then computes a current position of the A-GPS receiver using position location aiding information, certain satellite data and the position estimate of the A-GPS receiver.

Claims

1. A method for locating a position of an A-GPS receiver comprising:

receiving a cell identification code; and

retrieving, from a position cache, a position estimate for said A-GPS receiver that corresponds to said cell identification code, where said A-GPS receiver and said position cache are within a mobile device.

2. The method of claim 1 further comprising computing a current position of said A-GPS receiver using position location aiding information, satellite signals and said position estimate.

3. The method of claim 1 wherein said cell identification code is not found in said position cache said method further comprises:

transmitting said cell identification code to a aiding server;

associating a position estimate with the cell identification code;

transmitting the cell identification code and an associated position estimate from the aiding server to the mobile device;

receiving said cell identification code and an associated position estimate; and

storing said cell identification code and said associated position estimate in said position cache.

4. The method of claim 1 wherein said position cache comprises a look-up table.

5. The method of claim 4 wherein the lookup table comprises a first entry for said cell identification code and a second entry for said position estimate.

6. The method of claim 5 wherein said lookup table further comprises a third entry for short term position information.

7. The method of claim 6 wherein said short term position information is a position of the mobile device that was computed within a previous five minutes.

8. The method of claim 4 further comprises identifying a cell identification code for a cell of a cellular communications network within which the A-GPS receiver is operating.

9. The method of claim 1 wherein the position estimate is a location of a center of a cell in a wireless network, a location of a tower within the cell, or another location within the cell.

10. The method of claim 1 wherein the position estimate is the last known position of the A-GPS receiver within a cell identified by the cell identification code.

11. A mobile device comprising:

an A-GPS receiver; and

a position cache for storing a position estimate for the mobile device and a related cell identification code for a cell of a wireless network.

12. The mobile device of claim 11 wherein said position cache comprises a look-up table.

13. The mobile device of claim 11 wherein the lookup table comprises a first entry for a cell identification code and a second entry for a position estimate.

14. The mobile device of claim 13 wherein the first entry and second entry are created and stored for each cell of a cellular communications network that the mobile device uses for communication.

15. The mobile device of claim 14 wherein the lookup table further comprises a third entry for short term position information.

16. The mobile device of claim 15 wherein said short term position information is a position of the mobile device that was computed within a previous five minutes.

17. The mobile device of claim 11 wherein the position estimate is a location of a center of a cell in a wireless network, a location of a tower within the cell, or another location within the cell.

18. The mobile device of claim 11 wherein the position estimate is the last known position of the A-GPS receiver within a cell identified by the cell identification code.

19. A system for locating positions of mobile devices comprising:

at least one mobile device comprising an A-GPS receiver, a position cache and a wireless transceiver, where the position cache stores a position estimate for the mobile device and a related cell identification code for each cell of a wireless network that may be or was used by the at least one mobile device; and

a server in wireless communication with the mobile device.

20. The system of claim 19 wherein the wireless transceiver comprises a cellular telephone transceiver.

21. The system of claim 19 wherein said position cache comprises a look-up table.

22. The system of claim 21 wherein the lookup table comprises a first entry for a cell identification code and a second entry for a position estimate.

23. The system of claim 22 wherein the lookup table further comprises a third entry for short term position information.

24. The system of claim 23 wherein said short term position information is a position of the mobile device that was computed within a previous five minutes.