Multichannel Clutter Rejection in Spaceborne Bistatic Radar Systems Based on Joint Elevation-Azimuth-Doppler Adaptive Processing and Hybrid Auxiliary Channels

Because of the transmitter-receiver separation in a spaceborne bistatic radar system, the clutter Doppler frequency and spatial frequency will vary with range, affecting the clutter suppression performance. In addition, the range ambiguity will further intensify the influence of range-varying clutter since the spatial-temporal distributions of clutter in different range-ambiguous regions are different, producing additional filtering notches and more “blind regions” of moving target detection. To deal with this issue, a multichannel clutter suppression technique based on joint elevation-azimuth-Doppler adaptive processing and hybrid auxiliary channels is proposed in this paper. In this method, the clutter range dependence errors in the elevation, azimuth, and Doppler domains are firstly compensated by applying an adaptive three-dimensional compensation method. Then, after implementing the clutter localization in the elevation, azimuth, and time domains, a three-dimensional hybrid auxiliary channel based technique is utilized in the localized processing domain, where the optimal auxiliary channel selection is analyzed. Finally, the multichannel clutter suppression can be well realized in the joint elevation-azimuth-Doppler domain. The effectiveness of the proposed method is demonstrated through simulation results.