14 May 2018 Analysis of compressive approach to interference tagging in radio spectrometry
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Large-aperture, wide-band antenna arrays are important in both scientific (e.g., radio astronomy) and surveillance (e.g., radar) applications. The practical constraints of signal processing can limit these systems to produce a single (or few) beams, each of which is vulnerable to sidelobe interference. The disambiguation of legitimate (main lobe) signals from interference signals is of paramount importance in many applications. This paper considers time-modulated-array techniques for interference tagging as a mitigation approach and considers empirical statistics of interference detection vs. the beam-compressive ratio of a multi-beam system.

The time-modulated approach described in the paper expands on our previous work, in which it was demonstrated that alternating a real-time beamformer between multiple sets of weights can multiplex several different beams (acquisition and one or more sidelobe suppression) within the beamformer output for the same computational cost as a single beamformer. Alternating the weights based on pseudo-random codes implements a CDMA-like scheme, which exploits the frequency-domain sparsity of the received signals. Further, using a single SLS beam minimizes the impact on the resultant detection SNR, but our previous work showed that this also introduces challenges when the underlying array is spatially sparse.

The present work reported here will describe cost/performance tradeoffs of this technique when the number of auxiliary beams is changed; increasing this quantity will increase the probability of detection of RFI, but also will decrease the SNR (and PD) of weak target signals. This approach is compressive in the beam-space domain.
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William C. Barott, William C. Barott, Zhurong Wang, Zhurong Wang, } "Analysis of compressive approach to interference tagging in radio spectrometry", Proc. SPIE 10658, Compressive Sensing VII: From Diverse Modalities to Big Data Analytics, 106580N (14 May 2018); doi: 10.1117/12.2309305; https://doi.org/10.1117/12.2309305

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