Procedure for jammer detection
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.
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.
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.
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 .
10. A memory tangibly embodying the method of claim 3 .
11. The method of claim 1 wherein the localized portion of the correlation function is a Doppler segment.
12. The method of claim 3 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.
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.