Short-Range Clutter Suppression for Airborne Radar Using Sparse Recovery and Orthogonal Projection

For nonside-looking airborne radar (NSLAR), the range-dependent near-range clutter degrades the performance of space–time adaptive processing (STAP), especially in the high-pulse-repetition-frequency mode. To solve this problem, a novel algorithm using sparse recovery (SR) and orthogonal projection (OP) is proposed in this letter. First, the elevation angle of short-range clutter is estimated by the off-grid SR method. Second, the near-range clutter is suppressed in the elevation domain by the OP method. Finally, the azimuth–Doppler STAP is carried out to suppress the residual range-independent far-range clutter. The proposed algorithm can obtain the elevation angle of short-range clutter more precisely with only one training snapshot and it is robust since no prior knowledge is needed. The simulation results validate the effectiveness of the proposed algorithm.