Method and apparatus for signal processing in a satellite positioning system using navigation message common information

• US 8,078,118 B2
• Filed: 01/19/2010
• Issued: 12/13/2011
• Est. Priority Date: 05/06/1998
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc., Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm, Inc.
• Inventors: Krasner, Norman F.
• Primary Examiner(s): Cumming, William D
• Application Number:
  US12/689,922
• Publication Number:
  US 20100182197A1
• Time in Patent Office: 693 Days
• Field of Search: 342/357.63, 342/357.12, 342/357.1, 342/357.25, 342/357.42, 455/73, 455/456.1, 455/456.6, 375/150, 701/214
• US Class Current: 455/73
• CPC Class Codes: G01S 19/243 Demodulation of navigation message
• CPC Class Codes: G01S 19/246 involving long acquisition integration times, extended snapshots of signals or methods specifically directed towards weak signal acquisition
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0018 Transmission from mobile station to base station

Abstract

A method and apparatus for processing satellite positioning system (SPS) signals which are weak in level. In one embodiment, a SPS receiver receives at least two signal samples representing, at least in part, common information, wherein the two signal samples are associated with one or more satellite messages. By combining the two signal samples, navigation information (e.g., time, position, velocity, etc.) may be determined based on the combination of the two signal samples. According to another embodiment, the two signal samples are differentially demodulated and summed together to form the combination.

Claims

1. A method comprising:

at a mobile device, receiving a signal from a first satellite, the signal from the first satellite comprising a pseudorandom noise (PN) code portion and a navigation message portion both associated with the first satellite;

processing a first segment of the navigation message portion and a second segment of the navigation message portion, wherein the first segment and the second segment include common information, wherein processing the first segment of the navigation message portion and the second segment of the navigation message portion comprises checking consistency of common information in the first segment of the navigation message portion and the second segment of the navigation message portion and generating consistent common information therefrom;

subsequently accessing the consistent common information to determine position information of the mobile device.

2. The method of claim 1, wherein the common information comprises reference time information.

3. The method of claim 2, wherein the reference time information is a time of week (TOW), wherein the first segment of the navigation message portion is a first subframe and the second segment of the navigation message portion is a second subframe adjacent the first subframe.

4. The method of claim 3, wherein checking consistency of common information in the first segment of the navigation message portion and the second segment of the navigation message portion comprises checking that the TOW of the first subframe and the TOW of the second subframe differ by one.

5. The method of claim 3, wherein subsequently accessing the consistent common information to determine the position information of the mobile device comprises determining the time of week at a later subframe based on the TOW of the first subframe and the TOW of the second subframe.

6. The method of claim 1, wherein the position information of the mobile device comprises one or more pseudoranges.

7. The method of claim 1, wherein the position information of the mobile device comprises a position of the mobile device.

8. A method comprising:

at a mobile device, receiving a signal from a first satellite, the signal from the first satellite comprising a pseudorandom noise (PN) code portion and a navigation message portion both associated with the first satellite;

at the mobile device, receiving a signal from a second satellite, the signal from the second satellite comprising a pseudorandom noise (PN) code portion and a navigation message portion both associated with the second satellite

processing a first segment of the navigation message portion associated with the first satellite and a second segment of the navigation message portion associated with the second satellite, wherein the first segment and the second segment include common information, wherein processing the first segment and the second segment comprises checking consistency of common information in the first segment and the second segment and generating consistent common information therefrom;

subsequently accessing the consistent common information to determine position information of the mobile device.

9. The method of claim 8, wherein the common information comprises reference time information.

10. The method of claim 9, wherein the reference time information is a time of week (TOW), wherein the first segment of the navigation message portion associated with the first satellite is a first subframe and the second segment of the navigation message portion associated with the second satellite is a second subframe adjacent the first subframe.

11. The method of claim 10, wherein checking consistency of common information comprises checking that the TOW of the first subframe and the TOW of the second subframe differ by one.

12. The method of claim 10, wherein subsequently accessing the consistent common information to determine the position information of the mobile device comprises determining the time of week at a later subframe based on the TOW of the first subframe and the TOW of the second subframe.

13. The method of claim 8, wherein the position information of the mobile device comprises one or more pseudoranges.

14. The method of claim 8, wherein the position information of the mobile device comprises a position of the mobile device.

15. A mobile device comprising:

an SPS antenna to receive signals from one or more satellites, the signals from the one or more satellites comprising a pseudorandom noise (PN) code portion and a navigation message portion both associated with a particular satellite;

a processor to process a first segment of a navigation message portion associated with one of the one or more satellites and a second segment of the navigation message portion associated with one of the one or more satellites, wherein the first segment and the second segment include common information, wherein processing the first segment and the second segment comprises checking consistency of common information in the first segment and the second segment and generating consistent common information therefrom;

memory to store the consistent common information, wherein the processor is further configured to access the consistent common information to determine position information of the mobile device.

16. The mobile device of claim 15, wherein the position information comprises one or more pseudoranges.

17. The mobile device of claim 15, wherein the position information comprises a position of the mobile device.

18. The mobile device of claim 16, wherein the mobile device further comprises a communication subsystem to transmit the one or more pseudoranges to a network device.

19. A mobile device comprising:

means for receiving signals from one or more satellites, the signals from the one or more satellites each comprising a pseudorandom noise (PN) code portion and a navigation message portion both associated with a particular satellite;

means for processing a first segment of a navigation message portion associated with one of the one or more satellites and a second segment of the navigation message portion associated with one of the one or more satellites, wherein the first segment and the second segment include common information, wherein the means for processing the first segment and the second segment comprises means for checking consistency of common information in the first segment and the second segment and means for generating consistent common information therefrom;

means for storing the consistent common information;

means for accessing the consistent common information; and

means for determining position information of the mobile device.

20. The mobile device of claim 19, wherein the common information comprises reference time information.

21. The mobile device of claim 20, wherein the reference time information is a time of week (TOW), wherein the first segment is a first subframe and the second segment is a second subframe adjacent the first subframe.

22. The mobile device of claim 21, wherein the means for checking consistency of common information comprises means for checking that the TOW of the first subframe and the TOW of the second subframe differ by one.

23. The mobile device of claim 21, wherein the means for accessing the consistent common information to determine the position information of the mobile device comprises means for determining the time of week at a later subframe based on the TOW of the first subframe and the TOW of the second subframe.

24. The mobile device of claim 19, wherein the position information of the mobile device comprises one or more pseudoranges.

25. The mobile device of claim 19, wherein the position information of the mobile device comprises a position of the mobile device.