Ultra‐Low‐Complexity Doppler‐Spread Clutter Suppression in Ground‐Based Passive Radar

In ground‐based passive radar, the surveillance channel is mainly affected by zero‐Doppler clutter, while Doppler‐spread clutter caused by vegetation motion or structural vibration is also unavoidable in practice. Although the Doppler‐extended extensive cancellation algorithm (ECA) can effectively suppress both types of clutter, it incurs high computational and memory costs due to high‐dimensional subspace construction and associated computations, which may hinder real‐time target detection in practical applications. To address this issue, this paper proposes an ultra‐low‐complexity algorithm, termed ECA‐U, which avoids explicit subspace formation through circular shifts and frequency‐domain reuse of diagonal block structures. Simulation results demonstrate suppression performance comparable to Doppler‐extended ECA while achieving improvements of over an order of magnitude in runtime and storage efficiency.