An Accelerated Algorithm Based on GO-PO/PTD and CWMFSM for EM Scattering From the Ship Over a Sea Surface and SAR Image Formation

This article proposes an accelerated ray-tracing algorithm to improve the computational efficiency of composite scattering from the 3-D ship target located on a random sea surface. The ray tracing is accelerated by using a new neighbor search technique, with a new 0-1 transformation rule and arrangement of octree nodes. It can reduce the code complexity and improve the computational efficiency. Combined with this technique, an accelerated algorithm based on the geometrical optics, physical optics with physical theory of diffraction (GO-PO/PTD) and capillary wave modification facet scattering model (CWMFSM) is further established. This is meaningful for the simulation of scattered echoes for wideband synthetic aperture radar (SAR), enabling SAR images to be formed using an imaging algorithm. The effectiveness of the proposed method was verified by comparing the simulation results with those produced by the FEKO-based multilevel fast multipole method (MLFMM). Further confirmation of its accuracy was obtained by comparing the simulated images with the measured ship image.