Circular Trace Scanning SAR Imaging Based on Compressive Sensing

Abstract

The circular trace scanning synthetic aperture radar (CTSSAR) is a new imaging mode. It is similar to strip SAR mode when the antenna beam illuminates the observed area. But the trajectory of radar is a circle instead of the traditional straight line. These characteristics enable it to achieve fast wide-area imaging, which is very useful in both military and civilian fields. However, the traditional imaging algorithms for strip SAR cannot be directly used. Back projection algorithm can be used in this new imaging mode, but the reconstructed image is with high side-lobe. In this paper, an algorithm based on compressive sensing is proposed to obtain high quality image. Considering the short illuminate time for each observed object, the whole circular aperture is divided into several sub-apertures. For each sub-aperture, the compressive sensing algorithm is used. Then all the sub-aperture images are coherently combined into the final image. Point-target simulation results show that, this method can obtain high resolution image with low side-lobe even if the raw data is down sampled.