基于改进SBR的舰船SAR成像快速仿真计算方法

A Fast SAR Imaging Simulation Method of Ship Targets Based on Improved SBR

针对SAR(Synthetic Aperture Radar)舰船成像仿真应用中电磁散射特性计算效率低下的问题,在现有SBR(Shooting and Bouncing Rays)算法的基础上,本文提出两方面改进.一是基于叶节点空间邻域编码搜索的射线管相交面元检测算法,通过只追踪射线管中心射线并搜索叶节点空间周围潜在相交面元,在有效提升相交检测速度的同时避免遗漏相交面元;二是射线管三角剖分快速分裂算法,将射线管和相交面元投影至射线管虚拟孔径面,利用Delaunay三角剖分算法自适应地将射线管快速分裂成连续的子射线管.对典型舰船目标进行RCS(Radar Cross Section)计算及SAR成像仿真实验,结果表明,在保证计算精度的前提下,本文方法计算效率比Kd树(K-dimension tree)加速SBR方法提升14倍以上,比经典自适应射线管分裂SBR方法提升3倍以上,计算效率显著提高.

Aiming at the problem of low efficiency of electromagnetic scattering characteristics calculation in synthet⁃ic aperture radar(SAR)ship imaging simulation applications,two points of improvement based on the existing shooting and bouncing rays(SBR)technique are proposed in this work.Firstly,a ray tube intersecting surface panel detection algorithm with leaf node spatial neighborhood coding search is constructed,which effectively improves the intersection detection speed while avoiding missing intersecting panels by tracing only the center ray of the ray tube and searching for potential in⁃tersecting panels around the leaf node space.Secondly,a fast splitting technique for ray tube triangulation is introduced to project the ray tube and the intersecting panels to the ray tube’s virtual aperture surface,and adaptively split the ray tube in⁃to consecutive sub-ray tubes by using the Delaunay triangulation algorithm.Finally,the radar cross section(RCS)calcula⁃tion and SAR imaging simulation experiments are carried out on typical ship targets.The experimental results show that un⁃der the premise of ensuring the accuracy,the efficiency of the proposed method is improved by more than 14 times than that of the Kd(K-dimension)tree accelerated SBR and by more than 3 times compared with the classical adaptive ray tube split⁃ting SBR,showing that the computational efficiency is significantly promoted.