Back-Projection Imaging for Synthetic Aperture Radar with Topography Occlusion

Abstract

When synthetic aperture radar (SAR) is conducting remote sensing or terrain mapping, its radar beam is inevitably occluded by the variations in the under-test topography. Although back-projection algorithm (BPA) can theoretically directly solve the imaging problems of topography variations that most current SAR imaging algorithms cannot handle, these BPAs only solve the phase focusing of SAR echo signal, and do not consider the mismatch of SAR imaging results caused by topography occlusion. To solve the mis-imaging issue of the occluded area generated by BPA under the case of topography variation, a topography-based BPA (Topo-BPA) is proposed in this paper. Firstly, a new beam occlusion judgment algorithm based on spherical wave assumption is proposed, and its core is depression angle interpolation and depression angle updating. Then, the proposed Topo-BPA embeds the proposed beam occlusion judgment algorithm before the classical BPA, which not only did not reduce the focus depth of BPA, but improved the imaging accuracy of classical BPA. Finally, numerical experiments have demonstrated the superiority of the Topo-BPA’s performance in comparison with classical BPA.

An Efficient BP Algorithm Based on TSU-ICSI Combined with GPU Parallel Computing

“…In contrast, the classical backprojection (BP) algorithm conducts point-by-point phase compensation and coherent accumulation and does not necessitate approximation during the processing. This results in high imaging accuracy and broad applicability, thus meeting the demands for high-resolution SAR imaging [8,9].…”