Imaging Moving Targets for a Forward Scanning SAR without Radar Motion Compensation

Abstract

Forward scanning SAR (FS-SAR) has recently been presented as a new mode of imaging for automotive radars, providing enhanced azimuth resolution. FS-SAR has been extended to imaging moving objects. However, it is assumed that the radar motion has been pre-compensated. Therefore, image reconstruction and focusing have to deal with the movement of the target objects only. In practice, it is not easy to compensate for, especially, complex radar motion, perfectly. Therefore, in this paper, we modify the erstwhile approach of imaging moving targets with FS-SAR to allow for radar motion without compensation. Instead of a joint, image reconstruction and image/matrix decomposition, approach, we first reconstruct the target image for every aperture position and then apply matrix decomposition to separate moving targets from clutter/stationary objects. We show, via two FS-SAR reconstruction algorithms, namely, the compressed sensing based back-projection and the modified back-projection, that the proposed approach provides the benefits of improved imaging without the need for radar motion compensation. Real-data experiments corroborate the proposed methodology.