Autofocus in multistatic passive SAR imaging

Synthetic Aperture Radar (SAR) imaging suffers from image focus degradation in the presence of phase errors in the received signals due to unknown platform or target motion. We study automatic focusing (autofocus) under a multistatic passive scenario, where the illumination is provided by a set of stationary UHF transmitters and the goal is to image a moving aircraft. We employ heuristic iterative estimation algorithms that maximize a sharpness metric of the image. A similar method has been studied for the case of mono-static radar, where only one antenna is used for both transmitting and receiving. We present simulation results to help assess the effectiveness of the proposed autofocus approach.