A Fast 3-D Imaging Method for Circular SAR Based on 3-D Back-Projection Algorithm

Circular SAR (CSAR) is a typical 3-D imaging model of SAR. 3-D back-projection (BP) algorithm is a common time-domain 3-D imaging method for CSAR. However, 3-D imaging with back-projection algorithm has high algorithm complexity and low efficiency for processing pulse by pulse and grid by grid. This paper proposes a new fast 3-D imaging method for CSAR based on 3-D back-projection algorithm. In this method, 3-D interpolation and phase compensation operations can be transformed into 1-D interpolation and phase compensation operations and matrix searching operations with the construction of a geometric interpolation kernel. This proposed method can greatly improve imaging efficiency of CSAR when the error range allows. The simulated experimental results can prove the correctness and effectiveness of the proposed method.