Joint Autofocus and Stabilization for Video SAR by Residual Trajectory Deviation Estimating

Video synthetic aperture radar (Video-SAR) usually requires a combination of autofocus algorithms to ensure the quality of the image. However, due to the trajectory deviation and the jitter of the radar attitude, drift occurred on the video frame obtained by back projection (BP) algorithm, which affects the quality of the video. This paper proposes a joint autofocus and stabilization method for video SAR based on residual trajectory deviation estimation. Based on overlapping sub-aperture segmentation, this method first estimates the three-dimensional residual trajectory by joint autofocus by multiple sub-images, then the trajectory deviation between two overlapping sub-apertures is estimated by Kabsch algorithm, and finally, the video frame is stabilized by trajectory correction. Its performance has been demonstrated by experimental data acquired by a multirotor UAV Ku-band SAR system.