Recursive Sidelobe Minimization Algorithm for Back-Projection Imaging of Impulse-Based Circular Synthetic Aperture Radar

Circular synthetic aperture radar (CSAR) is of great significance in the detection of targets and their internal structure, such as mountains, the ground, and underground areas, because of its advantage of large total observation angle of the targets. Impulse-based radar has a very high range resolution but cannot be imaged by the azimuth focusing technique in the frequency domain. Therefore, the back-projection (BP) algorithm is used for imaging in this study. We derive the point spread function (PSF) analytic formula of the CSAR for BP algorithm imaging under a large total observation angle. According to the PSF, the influence of the strong scattering point on the adjacent image point is analyzed. Meanwhile, the problems of using the recursive sidelobe minimization (RSM) algorithm in CSAR are analyzed. Finally, combined with the above analysis, an improved RSM algorithm for impulse-based CSAR is proposed. Simulation and experimental data verify the accuracy and effectiveness of the proposed method.