LOCATION SPECIFIC SEARCH FOR REGIONAL SATELLITE VEHICLES

• US 20090318167A1
• Filed: 06/24/2008
• Published: 12/24/2009
• Est. Priority Date: 06/24/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Pon, Rayman Wai, Ristic, Borislav, Wu, Jie, Ische, Marc
• Granted Patent: US 8,620,306 B2
• Time in Patent Office: Days
• US Class Current: 455/456.200
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data

Abstract

A position location system, method, and apparatus are disclosed. A wireless device receives a first signal and obtains an identifier indicative of a first location from the first signal. The first signal can be received from a cellular base station and the first identifier can be a mobile country code. The wireless device uses the identifier to determine the availability of signals from a regional satellite system at the first location. If signals from the regional satellite system are available at the first location, the wireless device retrieves information associated with one or more satellite vehicles in the regional satellite system. The information can include pseudo-random number codes and a Doppler search range corresponding to the first location. The wireless device receives a second signal and processes the second signal to obtain first satellite signal information. The wireless device determines its position at least partially based on the first satellite signal information.

Claims

1. A position location method for a wireless device comprising:

receiving a first signal;

obtaining an identifier indicative of a first location from the first signal;

retrieving information associated with at least one satellite vehicle using the identifier, the at least one satellite vehicle belonging to a regional satellite system;

receiving a second signal;

processing the second signal to obtain first satellite signal information for the at least one satellite vehicle; and

determining a position of the wireless device at least partially based on the first satellite signal information.

2. The method of claim 1 wherein the identifier comprises a country code corresponding to the first location.

3. The method of claim 1 wherein receiving the first signal further comprises receiving a signal from a cellular base station.

4. The method of claim 1, wherein processing the second signal to obtain the first satellite signal information comprises processing the second signal using a limited Doppler search range prior to accessing current satellite orbital information.

5. The method of claim 1 wherein the identifier comprises a world time zone of the first location.

6. The method of claim 1 wherein the first identifier comprises at least a portion of a network address of the wireless device.

7. The method of claim 1 further comprising updating the information associated with the at least one satellite vehicle.

8. The method of claim 1 wherein retrieving the information associated with the at least one satellite vehicle further comprises accessing data in a non-volatile storage of the wireless device.

9. The method of claim 1 wherein the information associated with the at least one satellite vehicle comprises a pseudo-random number code (PRN) used for coding the first satellite signal.

10. The method of claim 9 wherein processing the second signal comprises:

generating a reference signal using the pseudo-random number code; and

cross-correlating the second signal and the reference signal.

11. The method of claim 1 wherein the information associated with the at least one satellite vehicle comprises a Doppler search range corresponding to the first location, and wherein processing the second signal comprises searching for a carrier of the at least one satellite vehicle based on the Doppler search range.

12. The method of claim 1 wherein the regional satellite system is selected from the group consisting of the Wide Area Augmentation System (WAAS), European Geostationary Overlay Service (EGNOS), MTSAT Satellite-based Augmentation System (MSAS), Quasi-Zenith Satellite System (QZSS), GPS Aided Geo Augmented Navigation (GAGAN), and Indian Regional Navigation Satellite System (IRNSS) systems.

13. The method of claim 1 further comprising:

while obtaining the first satellite signal information, processing the second signal to obtain second satellite signal information for a second satellite vehicle, wherein the second satellite vehicle is part of a global navigation satellite system (GNSS).

14. The method of claim 13 wherein the global navigation satellite system is selected from the group consisting of the GPS, GLONASS, GALILEO, and COMPASS systems.

15. The method of claim 1 further comprising:

determining an orbital type of the at least one satellite vehicle; and

retrieving a Doppler search range corresponding to the at least one satellite vehicle if the orbital type is determined to be geosynchronous; and

wherein processing the second signal comprises limiting a search for the first satellite signal based on the Doppler search range.

16. The method of claim 1 wherein the first location is a country within a coverage area of the Quasi-Zenith Satellite System (QZSS), the method further comprising:

retrieving a Doppler search range corresponding to the at least one satellite vehicle for the country indicated by the identifier; and

limiting a search for the first satellite signal based on the Doppler search range.

17. A wireless device comprising:

a first receiver configured to receive an information bearing signal having a first identifier indicative of a first location;

a second receiver configured to receive a plurality of satellite signals and to determine a position of the wireless device using information from the plurality of satellite signals, wherein the second receiver receives at least one of the plurality of satellite signals using second identifiers for satellite vehicles that are part of a regional satellite system; and

a processor configured to obtain the first identifier from the information bearing signal and to use the first identifier to retrieve the second identifiers from a memory of the wireless device.

18. The wireless device of claim 17 wherein the second identifiers are associated with satellite vehicles that are part of at least one regional satellite system having the first location within its coverage area.

19. The wireless device of claim 17 wherein the first receiver receives the information bearing signal from a cellular base station.

20. The wireless device of claim 19 wherein the first identifier comprises a country code associated with the cellular base station.

21. The wireless device of claim 17 wherein the first identifier comprises a world time zone of the first location.

22. The wireless device of claim 17 wherein the first identifier comprises a portion of a network address of the wireless device and the processor is configured to retrieve the second identifiers from the memory based upon the portion of the network address.

23. The wireless device of claim 17 wherein the first identifier comprises a country code and the processor is configured to retrieve the second identifiers from the memory based on the country code.

24. The wireless device of claim 17 wherein the memory comprises a non-volatile memory and the second identifiers are stored in the non-volatile memory.

25. The wireless device of claim 17 wherein the processor is configured to update the first and second identifiers in the memory.

26. The wireless device of claim 17 wherein the second identifiers comprise at least one pseudo-random number (PRN) code for the satellite vehicles that are part of the regional satellite system.

27. The wireless device of claim 26 wherein the second receiver is configured to generate a reference signal using one of the at least one pseudo-random numbers and to cross-correlate the at least one of the plurality of satellite signals with the reference signal.

28. The wireless device of claim 17 wherein the processor uses the first identifier to retrieve a Doppler search range corresponding to the first location and the second receiver searches for a carrier of the at least one of the plurality of satellite signals based on the Doppler search range.

29. The wireless device of claim 17 wherein the regional satellite system is selected from the group consisting of the Wide Area Augmentation System (WAAS), European Geostationary Overlay Service (EGNOS), MTSAT Satellite-based Augmentation System (MSAS), Quasi-Zenith Satellite System (QZSS), GPS Aided Geo Augmented Navigation (GAGAN) system, and Indian Regional Navigation Satellite System (IRNSS) systems.

30. The wireless device of claim 17 wherein the second receiver receives signals from a global navigation satellite system (GNSS) using third identifiers and concurrently receives the at least one of the plurality of satellite signals using the second identifiers.

31. The wireless device of claim 30 wherein the global satellite positioning system is selected from the group consisting of the GPS, GLONASS, GALILEO, and the COMPASS systems.

32. The wireless device of claim 17 wherein the processor determines an orbital type of the satellite vehicles that are part of the regional satellite system and retrieves a Doppler search range from the memory if the orbital type is geosynchronous, and wherein the second receiver limits a search for a carrier frequency of the at least one of the plurality of satellite signals based on the Doppler search range.

33. The wireless device of claim 17 wherein the first identifier is indicative of a country and the regional satellite system is the Quasi-Zenith Satellite System (QZSS), the processor being configured to retrieve a Doppler search range corresponding to the QZSS satellite vehicles and to the country indicated by the identifier, and wherein the second receiver limits a search for a carrier frequency of the at least one of the plurality of satellite signals based on the Doppler search range.

34. A position location method for a mobile device comprising:

maintaining information associated with satellite vehicles of regional satellite systems in a memory of the mobile device;

receiving a terrestrial signal from a cellular base station;

obtaining an identifier indicative of a first location from the terrestrial signal;

determining the availability of a first regional satellite system at the first location using the identifier;

retrieving from the memory a pseudo-random number code corresponding to a first satellite vehicle of the first regional satellite system if the first regional satellite system is available at the first location;

receiving a second signal;

processing the second signal using the pseudo-random number code to obtain first satellite signal information; and

determining a position of the mobile device at least partially based on the first satellite signal information.

35. The position location method of claim 34, wherein processing the second signal to obtain the first satellite signal information comprises processing the second signal using a limited Doppler search range prior to accessing current satellite orbital information.

36. The position location method of claim 34 further comprising:

retrieving from the memory a Doppler search range corresponding to the first satellite vehicle at the first location, and

wherein processing the second signal comprises searching for a carrier of the first satellite vehicle based on the Doppler search range.

37. The position location method of claim 34 further comprising:

displaying information associated with the first regional satellite system if the first regional satellite system is available at the first location.

38. The position location method of claim 34 further comprising:

while obtaining the first satellite signal information, processing the second signal to obtain second satellite signal information for a second satellite vehicle, wherein the second satellite vehicle is part of a global navigation satellite system (GNSS).

39. The position location method of claim 34 wherein the first location is within a coverage area of the Quasi-Zenith Satellite System (QZSS) system, the method further comprising:

determining a Doppler search range associated with the first satellite vehicle and the first location.

40. A computer-readable medium encoded with one or more instructions for locating the position of a wireless device, the one or more instructions including instructions which, when executed by one or more processors, cause the one or more processors to perform steps of:

receiving a first signal;

obtaining an identifier indicative of a first location from the first signal;

retrieving information associated with at least one satellite vehicle using the identifier, the at least one satellite vehicle belonging to a regional satellite system;

receiving a second signal;

processing the second signal to obtain first satellite signal information for the at least one satellite vehicle; and

determining a position of the wireless device at least partially based on the first satellite signal information.

41. A wireless device comprising:

means for receiving an information bearing signal having a first identifier indicative of a first location;

means for receiving a plurality of satellite signals and determining a position of the wireless device using information from the satellite signals, wherein at least one of the plurality of satellite signals is received using second identifiers for satellite vehicles that are part of a regional satellite system; and

means for obtaining the first identifier from the information bearing signal and using the first identifier to retrieve the second identifiers from a storage means of the wireless device.