A Nonstationary Clutter Suppression Algorithm for Space-Based Radar Based on Presequence Pulse Echoes

Owing to the Earth's rotation and the rapid motion of satellites, the clutter received by space-based radar (SBR) exhibits severe nonstationary characteristics, notably evidenced by the Doppler frequency of clutter varying with range, particularly in the near-range region. Elevation prefiltering is shown to be an effective algorithm for suppressing near-range nonstationary clutter. Based on the characteristics of SBR with several near-range bending clutters, this article proposes an elevation prefiltering algorithm based on presequence pulse echoes to suppress nonstationary clutter for SBR. The training samples selected only contain near-range nonstationary clutter, which is obtained from the elevation dimension data of the presequence pulse echoes. By excluding the influence of far-range clutter, the proposed algorithm demonstrates superior performance in suppressing near-range clutter. After attenuating the near-range nonstationary clutter, the azimuth-Doppler space-time adaptive processing algorithm is cascaded to further suppress far-range stationary clutter. Simulation results show the effectiveness in suppressing near-range clutter and enhancing target detection capabilities for SBR of the proposed method.