MIMO SAR processing for multichannel high-resolution wide-swath radars

This paper addresses signal reconstruction for future multiple-input multiple-output synthetic aperture radars (SARs) equipped with a multichannel antenna to enable wide-area high-resolution imaging. To image large swaths without range ambiguities, these high-resolution wide-swath (HRWS) SAR systems use a low pulse repetition frequency (PRF). Such a PRF, however, causes the radar echoes received by each channel to be strongly aliased. By introducing new techniques, this paper extends the theory of multichannel signal processing for reconstructing the SAR signal from the aliased signals. The reconstruction performances of the proposed processing methods in terms of signal-to-noise ratio, resolution, point target ambiguity ratio, peak-to-sidelobe ratio, and signal-to-ambiguity-plus-noise ratio are investigated according to the PRF and compared with each other for an exemplary HRWS SAR system.