Space-time adaptive processing for range-folded spread-Doppler radar clutter mitigation

This paper concerns the detection of radar targets masked by Doppler-spread surface backscatter from points beyond the radar´s maximum unambiguous range. Current methods for mitigating this so-called “range-folded” clutter, such as reducing the pulse-repetition frequency or the use of nonrecurrent waveforms, typically involve some loss in the useable Doppler space fraction available for target detection. This paper uses blind source separation methods to exploit the known Doppler separation afforded by non-recurrent waveforms in order to estimate the spatial wavefront of the clutter across a linear receive array. Spatial adaptive processing using this estimated wavefront is then used to suppress range-folded clutter without sacrificing usable Doppler space. Simulation results are presented which quantify performance in terms of SCNR gain achieved.