SYSTEM AND/OR METHOD FOR DETECTING MULTI-TONE JAMMING

• US 20090268788A1
• Filed: 04/28/2008
• Published: 10/29/2009
• Est. Priority Date: 04/28/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chen, Shiou-Hung, Simic, Emilija M., Grover, Douglas
• Granted Patent: US 8,094,702 B2
• Time in Patent Office: Days
• US Class Current: 375/150
• CPC Class Codes: G01S 19/21 Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service
• CPC Class Codes: H04K 3/224 with countermeasures at transmission and/or reception of the jammed signal, e.g. stopping operation of transmitter or receiver, nulling or enhancing transmitted power in direction of or at frequency of jammer
• CPC Class Codes: H04K 3/90 related to allowing or preventing navigation or positioning, e.g. GPS

Abstract

The subject matter disclosed herein relates to a system and method for processing a signal received from a satellite positioning system (SPS) in the presence of a multi-tone jammer. In one particular implementation, processing of a signal may be altered in response to detection of one or more conditions.

Claims

1. A method comprising:

processing a received satellite positioning system (SPS) signal to obtain a correlation peak detection in a code phase search window comprising a range of code phase hypotheses;

detecting one or more energy peaks in said processed SPS signal; and

altering said processing in response to detecting a maximum energy peak within a set range of code phase hypotheses of a boundary of said code phase search window.

2. The method of claim 1, wherein said altering said processing further comprises:

shifting said code phase search window; and

processing said received SPS signal according to said shifted code phase search window.

3. The method of claim 2, wherein said processing said received SPS signal according to said shifted code phase search window further comprises:

rejecting energy in a Doppler region associated with at least one of said one or more detected energy peaks.

4. The method of claim 3, wherein said processing said received SPS signal according to said shifted code phase search window further comprises detecting a correlation peak based, at least in part, on one or more un rejected energy peaks.

5. The method of claim 3, wherein said rejecting energy in said Doppler region associated with at least one of said one or more detected energy peaks further comprises rejecting said energy in said Doppler region based, at least in part, on a comparison of energy values of energy peaks detected in said Doppler region.

6. The method of claim 3, wherein rejecting energy in said Doppler region further comprises rejecting said energy based, at least in part, on a comparison of an energy value of at least one peak in said Doppler region with an average noise level in said Doppler region.

7. The method of claim 1, wherein said altering said processing further comprises extending an integration time to allow detection of additional energy peaks in said code phase search window.

8. The method of claim 7, wherein said extending said integration time comprises suspending early termination of integration to obtain an energy result.

9. The method of claim 1, wherein said set range of code phase hypotheses comprises a set number of chips in a pseudonoise code sequence.

10. The method of claim 1, wherein said maxim energy peak comprises a most likely valid maximum energy peak.

11. A method comprising:

processing a received satellite positioning system (SPS) signal to obtain a correlation peak detection in a code phase search window comprising a range of code phase hypotheses;

detecting two or more energy peaks in said processed SPS signal; and

altering said processing in response to detecting energy peaks spaced apart by more than a set spacing in said range of code phase hypotheses.

12. The method of claim 11, wherein said set spacing is based, at least in part, on a maximum spacing of an energy peak from detection of a later multipath signal and an energy peak resulting from detection of a multipath signal.

13. The method of claim 11, wherein said altering said processing further comprises extending an integration time to allow detection of additional energy peaks in said code phase search window.

14. The method of claim 13, wherein said extending said integration time comprises suspending early termination of integration to obtain an energy result.

15. A mobile station comprising:

a receiver adapted to receive and downconvert an SPS signal; and

a baseband processor, said baseband processor being adapted to;

process said downconverted SPS signal to obtain a correlation peak detection in a code phase search window comprising a range of code phase hypotheses;

detect one or more energy peaks in said processed SPS signal; and

alter said processing in response to detecting a maximum energy peak within a set range of code phase hypotheses of a boundary of said code phase search window.

16. The mobile station of claim 15, wherein said baseband processor is further adapted to alter said processing in response to said detecting by:

shifting said code phase search window; and

processing said received SPS signal according to said shifted code phase search window.

17. The mobile station of claim 16, wherein said processing said received SPS signal according to said shifted code phase search window further comprises:

rejecting energy in a Doppler region associated with at least one of said one or more detected energy peaks.

18. The mobile station of claim 17, wherein said processing said received SPS signal according to said shifted code phase search window further comprises:

detecting a code phase based, at least in part, on one or more un rejected energy peaks.

19. The mobile station of claim 15, wherein said baseband processor is further adapted to alter said processing in response to said detecting by extending an integration time to allow detection of additional energy peaks in said code phase search window.

20. The mobile station of claim 15, wherein said range of code phase hypotheses comprises a set number of chips in a pseudonoise code sequence.

21. The mobile station of claim 15, wherein said maxim energy peak comprises a most likely valid maximum energy peak.

22. A mobile station comprising:

a receiver adapted to receive and downconvert an SPS signal; and

a baseband processor, said baseband processor being adapted to;

process said downconverted SPS signal to detect a correlation peak in a code phase search window, the code phase search window comprising a range of code phase hypotheses;

detect two or more energy peaks in said processed SPS signal; and

alter said processing of said downconverted SPS signal in response to detecting said energy peaks spaced apart by more than a set spacing in said range of code phase hypotheses bins.

23. The mobile station of claim 22, wherein said set spacing is based, at least in part, on a maximum spacing of an energy peak from a true code phase detection and a peak resulting from detection of a multipath signal.

24. The mobile station of claim 22, wherein said baseband processor is adapted to alter said processing in response to said detecting by extending an integration time to detect additional energy peaks in said code phase search window.

25. The mobile station of claim 24, wherein said extending said integration time comprises suspending early termination of integration to obtain an energy result.

26. An article comprising:

a storage medium, said storage medium having machine readable instructions stored thereon which, if executed by a computing platform, are adapted to enable said computing platform to;

control processing of a downconverted SPS signal to detect a correlation peak in a code phase search window comprising a range of code phase hypotheses;

detect one or more energy peaks in said processed SPS signal; and

alter said processing in response to detecting a maximum energy peak within a range of code phase hypotheses of a boundary of said code phase search window.

27. The article of claim 26, wherein said maximum energy peak comprises a most likely valid maximum energy peak.

28. An article comprising:

a storage medium, said storage medium having machine readable instructions stored thereon which, if executed by a computing platform, are adapted to enable said computing platform to;

control processing of a downconverted SPS signal to detect a correlation peak in a code phase search window comprising a range of code phase hypotheses;

detect two or more energy peaks in said processed SPS signal; and

alter said processing of said downconverted SPS signal in response to detecting energy peaks spaced apart by more than a set spacing in said range of code phase hypotheses.

29. An apparatus comprising:

means for processing a received satellite positioning system (SPS) signal to obtain a correlation peak detection in a code phase search window comprising a range of code phase hypotheses;

means for detecting one or more energy peaks in said processed SPS signal; and

means for altering said means for processing in response to detecting a maximum energy peak within of a range of code phase hypotheses of a boundary of said code phase search window.

30. The apparatus of claim 29, wherein said means for altering said means for processing further comprises:

means for shifting said code phase search window; and

means for processing said received SPS signal according to said shifted code phase search window.

31. The apparatus of claim 29, wherein said means for processing said received SPS signal according to said shifted code phase search window further comprises:

means for rejecting energy in a Doppler region associated with at least one of said one or more detected energy peaks.

32. The apparatus of claim 31, wherein said means for processing said received SPS signal according to said shifted code phase search window further comprises:

means for detecting a correlation peak based, at least in part, on one or more un-rejected energy peaks.

34. The apparatus of claim 31, wherein means for rejecting energy in said Doppler region associated with at least one of said one or more detected energy peaks further comprises means for rejecting said energy in said Doppler region based, at least in part, on a comparison of energy values of energy peaks detected in said Doppler region.

35. The apparatus of claim 31, wherein means for rejecting energy in said Doppler region further comprises means for rejecting said energy based, at least in part, on a comparison of an energy value of at least one peak in said Doppler region with an average noise level in said Doppler region.

36. The apparatus of claim 29, wherein said means for altering said means processing further comprises means for extending an integration time to detect additional energy peaks in said code phase search window.

37. The apparatus of claim 36, wherein said means for extending said integration time comprises means for suspending early termination of integration to obtain an energy result.

38. An apparatus comprising:

means for processing a received satellite positioning system (SPS) signal to detect a correlation peak in a code phase search window comprising a range of code phase bins associated with code phase hypotheses;

means for detecting two or more energy peaks in said processed SPS signal; and

means for altering said processing in response to detecting energy peaks spaced apart by more than a set spacing in said range of code phase bins.

39. The apparatus of claim 38, wherein said set spacing is based, at least in part, on a maximum spacing of an energy peak resulting from detection of a later multipath and a peak resulting from detection of a multipath signal.

40. The apparatus of claim 38, wherein said means for altering said processing further comprises means for extending an integration time to allow detection of additional energy peaks in said code phase search window.

41. The apparatus of claim 40, wherein said means for extending said integration time comprises suspending early termination of integration to obtain an energy result.