Receiver for detecting signals in the presence of high power interference

1. A RF receiver comprising:

a complex mixer for converting a version of an input RF signal to an input complex baseband signal comprising an input in-phase component and an input quadrature component;

one or more analog-to-digital converters (ADCs) connected to the complex mixer for digitizing the input in-phase component and the input quadrature component of the input complex baseband signal; and

a digital signal processor (DSP) connected the one or more ADCs, wherein the DSP is programmed to mitigate interference in the input complex baseband signal by:

performing at least one cross correlation operation involving L-length segments of the digitized input in-phase and input quadrature components of the input complex baseband signal; and

concatenating the cross-correlated L-length segments of the digitized input in-phase and input quadrature components of the input complex baseband signal to produce digitized interference mitigated in-phase and quadrature components of the input complex baseband signal.

2. The receiver of claim 1 , wherein the at least one cross correlation operation comprises two or more iterative cross correlation operations involving the L-length segments of the digitized input in-phase and input quadrature components of the input complex baseband signal.

3. The receiver of claim 1 , wherein the DSP is programmed to construct a reference signal for mitigating the interference by clipping and filtering the digitized input in-phase and input quadrature components of the digitized complex baseband signal.

4. The receiver of claim 2 , wherein the DSP is programmed to mitigate interference in the digitized complex baseband signal by independently clipping the digitized input in-phase and input quadrature components of the input complex baseband signal prior to performing two or more iterative cross correlation operations.

5. The receiver of claim 1 , wherein the DSP is further programmed to demodulate the digitized interference mitigated in-phase and quadrature components of the input complex baseband signal to produce a demodulated digital signal.

6. The receiver of claim 4 , wherein the DSP is further programmed to demodulate the digitized interference mitigated in-phase and quadrature components of the input complex baseband signal to produce a demodulated digital signal.

7. The receiver of claim 6 , wherein the DSP is programmed to demodulate the digitized interference mitigated in-phase and quadrature components of the input complex baseband signal using a digital FM demodulation scheme.

8. The receiver of claim 5 , wherein the DSP is further programmed to compute an estimate of an amplitude of one or more tones present in the demodulated digitized signal.

9. The receiver of claim 7 , wherein the DSP is further programmed to compute an estimate of an amplitude of one or more tones present in the demodulated digitized signal.

10. The receiver of claim 1 , wherein the DSP is further programmed to compute an estimate of an amplitude of one or more tones present in the input complex baseband signal.

11. The receiver of claim 8 , wherein the DSP is programmed to compute the estimate of the amplitude of a first tone present in the demodulated digitized signal by a process that comprises the steps of:

segmenting the demodulated digitized signal into a plurality of segments;

cross-correlating the plurality of segments of the demodulated digitized signal with sampled versions of in-phase and quadrature components the first tone to generate amplitude estimates of the in-phase and quadrature components of the first tone for each of the plurality of segments;

weighting each of the plurality of segments of the in-phase and quadrature components of the first tone; and

summing the weighted segments for the in-phase and quadrature components of the first tone.

12. The receiver of claim 11 , wherein:

the DSP further is programmed to estimate the signal-to-interference plus noise ratio for each of the plurality of segments; and

weighting each of the plurality of segments of the in-phase and quadrature components of the first tone comprises weighting each of the plurality of segments of the in-phase and quadrature components of the first tone with a weight based on the signal-to-interference plus noise ratio for the segment.

13. The receiver of claim 9 , wherein the DSP is programmed to compute the estimate of the amplitude of a first tone present in the demodulated digitized signal by a process that comprises the steps of:

segmenting the demodulated digitized signal into a plurality of segments;

cross-correlating the plurality of segments of the demodulated digitized signal with sampled versions of in-phase and quadrature components the first tone to generate amplitude estimates of the in-phase and quadrature components of the first tone for each of the plurality of segments;

weighting each of the plurality of segments of the in-phase and quadrature components of the first tone; and

summing the weighted segments for the in-phase and quadrature components of the first tone.

14. The receiver of claim 13 ,

further comprising estimating the signal-to-interference plus noise ratio for each of the plurality of segments; and

wherein weighting each of the plurality of segments of the in-phase and quadrature components of the first tone comprises weighting each of the plurality of segments of the in-phase and quadrature components of the first tone with a weight based on the signal-to-interference plus noise ratio for the segment.

15. A method comprising:

receiving, by an antenna of a receiver, an input modulated RF signal;

converting, by a complex mixer of the receiver, a version of the input modulated RF signal to an input complex baseband signal comprising an input in-phase component and an input quadrature component;

digitizing the input in-phase component and the input quadrature component of the input complex baseband signal with one or more analog-to-digital converters (ADCs) connected to the complex mixer; and

mitigating interference in the digitized complex baseband with a signal a digital signal processor (DSP) connected the one or more ADCs by:

performing at least one cross correlation operation involving L-length segments of the digitized input in-phase and input quadrature components of the input complex baseband signal; and

concatenating the cross-correlated L-length segments of the digitized input in-phase and input quadrature components of the input complex baseband signal to produce digitized interference mitigated in-phase and quadrature components of the input complex baseband signal.

16. The method of claim 15 , wherein mitigating the interference further comprises clipping and filtering the digitized input in-phase and input quadrature components of the input complex baseband signal.

17. The method of claim 15 , further comprising digitally demodulating, by the DSP, the digitized interference mitigated in-phase and quadrature components of the input complex baseband signal to produce a demodulated digital signal.

18. The method of claim 17 , further comprising computing, by the DSP, an estimate of an amplitude of one or more tones present in the demodulated digitized signal.

19. The method of claim 18 , wherein computing the estimate of the amplitude of one or more tones present in the demodulated digitized signal comprises computing the estimate of the amplitude of a first tone present in the demodulated digitized signal by a process that comprises the steps of:

segmenting the demodulated digitized signal into a plurality of segments;

cross-correlating the plurality of segments of the demodulated digitized signal with sampled versions of in-phase and quadrature components the first tone to generate amplitude estimates of the in-phase and quadrature components of the first tone for each of the plurality of segments;

weighting each of the plurality of segments of the in-phase and quadrature components of the first tone; and

summing the weighted segments for the in-phase and quadrature components of the first tone.

20. The method of claim 19 , further comprising estimating, by the DSP, the signal-to-interference plus noise ratio for each of the plurality of segments; and

wherein weighting each of the plurality of segments of the in-phase and quadrature components of the first tone comprises weighting each of the plurality of segments of the in-phase and quadrature components of the first tone with a weight based on the signal-to-interference plus noise ratio for the segment.

21. The system of claim 3 wherein the reference signal is a scaled version of estimates of the input inphase and input quadrature components of the interference present in the input complex baseband signal.