Temporal rate up-conversion of synthetic aperture radar via low-rank matrix recovery

The radar data to form synthetic aperture radar (SAR) imagery is normally transmitted and received by moving platforms like aircraft or vehicles. In many situations, the platforms move at high speed; which reduces the number of sampling records collected to the synthetic aperture, hence degrades the quality of the reconstructed SAR images. Therefore, it is necessary to develop an algorithm that is capable of increasing the temporal frequency rate of the received data. In this paper, we propose a novel technique to generate intermediate records from the existing ones by a locally-adaptive low-rank matrix recovery framework. The system first fills in the blank records using a bi-directional motion estimation scheme. The initialized aperture records are then refined by a robust low-rank matrix completion algorithm using the reference from neighborhood clean records. Experiments demonstrate that the proposed method provides comparative results when up-converting the aperture rate by a factor of two or four, both in mean square error of the raw SAR signal and PSNR performance of the recovered SAR images.