Procedure for jammer detection

• US 7,127,011 B2
• Filed: 08/29/2002
• Issued: 10/24/2006
• Est. Priority Date: 08/29/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rowitch, Douglas N.
• Primary Examiner(s): Tran, Khai
• Application Number:
  US10/232,637
• Publication Number:
  US 20040042568A1
• Time in Patent Office: 1,517 Days
• Field of Search: 375/346, 375/254, 375/278
• US Class Current: 375/346
• 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 3/22 including jamming detection and monitoring
• CPC Class Codes: H04K 3/90 related to allowing or preventing navigation or positioning, e.g. GPS

Abstract

A method of and system for detecting whether a peak of a correlation function derived from a received signal is due to a jammer. The peak is within a localized portion of the correlation function which has a total number of peaks. In one embodiment, the total number of peaks is compared to a threshold number of peaks, and the peak is identified as being due to a jammer if the total number of peaks equals or exceeds a threshold number of peaks. In a second embodiment, the peak energy in relation to a noise estimate for the localized portion of the correlation function is compared to a jammer threshold. The peak is identified as being due to a jammer if the peak energy in relation to the noise estimate is less than or equal to the jammer threshold.

Claims

1. A method of detecting whether a peak of a correlation function derived from a received signal is due to a jammer, said peak being within a localized portion of the correlation function having a total number of peaks, comprising:

comparing the total number of peaks with a threshold number of peaks; and

identifying said peak as being due to a jammer if the total number of peaks equals or exceeds the threshold.

2. The method of claim 1 wherein the total number of peaks within the localized portion of the correlation function define a plurality of peaks, and the identifying step comprises identifying all of the peaks in said plurality of peaks as being due to a jammer if the total number of peaks equals or exceeds the threshold.

8. The method of claim 1 wherein the localized portion of the correlation function comprises a plurality of samples including peak and non-peak samples, and the identifying step comprises identifying said peak as being due to a jammer if the number of non-peak samples is less than or equal to a threshold number of samples.

9. A memory tangibly embodying the method of claim 1.

11. The method of claim 1 wherein the localized portion of the correlation function is a Doppler segment.

13. The method of claim 8 wherein the identifying step comprises identifying all of the peaks within the localized portion of the correlation function as being due to a jammer if the number of non-peak samples is less than or equal to the threshold number of samples.

14. A system for detecting whether a peak of a correlation function derived from a received signal is due to a jammer comprising a processor and the memory of claim 9, wherein the processor is configured to access and execute the software instructions tangibly embodied by the memory.

3. A method of detecting whether a peak of a correlation function derived from a received signal is due to a jammer, the peak being within a localized portion of the correlation function having a noise estimate, and the peak having a peak energy, comprising;

comparing the peak energy in relation to the noise estimate to a jammer threshold; and

identifying the peak as being due to a jammer if the peak energy in relation to the noise estimate is less than or equal to the jammer threshold.

4. The method of claim 3 wherein the noise estimate is a mean measured noise estimate.

5. The method of claim 4 wherein the identifying step comprises identifying the peak as being due to a jammer if the peak energy is less than or equal to the product of the jammer threshold and the mean measured noise estimate.

6. The method of claim 4 wherein the localized portion of the correlation function comprises a plurality of samples including peak and non-peak samples, and the mean measured noise estimate is derived by averaging the non-peak samples.

7. The method of claim 6 wherein each peak in the localized portion is characterized by a peak sample and two adjacent samples, and the non-peak samples comprise all the samples in the plurality of samples except for the peak and adjacent samples.

10. A memory tangibly embodying the method of claim 3.

12. The method of claim 3 wherein the localized portion of the correlation function is a Doppler segment.

15. A system for detecting whether a peak of a correlation function derived from a received signal is due to a jammer comprising a processor and the memory of claim 10, wherein the processor is configured to access and execute the software instructions tangibly embodied by the memory.

16. A method of detecting whether a peak of a correlation function derived from a received signal is due to a jammer, said peak being within a localized portion of the correlation function having a total number of peaks, comprising:

a step for comparing the total number of peaks with a threshold number of peaks; and

a step for identifying said peak as being due to a jammer if the total number of peaks equals or exceeds the threshold.

17. A method of detecting whether a peak of a correlation function derived from a received signal is due to a jammer, the peak being within a localized portion of the correlation function having a noise estimate, and the peak having a peak energy, comprising:

a step for comparing the peak energy in relation to the noise estimate to a jammer threshold; and

a step for identifying the peak as being due to a jammer if the peak energy in relation to the noise estimate is less than or equal to the jammer threshold.