基于改进SBR技术的地面目标SAR图像快速生成技术  

Efficient SAR image simulation for target on rough ground surface using the improved SBR technique

作　　者：单敬喆 曲晓杰[2] 晁坤[2] 许小剑[1] SHAN Jingzhe;QU Xiaojie;CHAO Kun;XU Xiaojian(School of Electronics and Information Engineering,Beihang University,Beijing 100191,China;China Research Institute of Radiowave Propagation,Qingdao 266107,China)

机构地区：[1]北京航空航天大学电子信息工程学院,北京100191 [2]中国电波传播研究所,青岛266107

出　　处：《电波科学学报》2024年第2期322-331,共10页Chinese Journal of Radio Science

基　　金：中国电波传播研究所稳定支持科研经费(A132003W02)。

摘　　要：传统的弹跳射线(shooting and bouncing ray,SBR)技术主要适用于自由空间目标的电磁散射计算,当用于地面目标与背景复合场景的电磁散射计算和合成孔径雷达(synthetic aperture radar,SAR)图像建模与仿真时,在小擦地角下其计算误差显著增大。针对此问题,提出了一种基于“四路径”模型的改进SBR技术,其考虑了目标与邻域地面之间的多次反射效应以及目标与远区地面之间的多径散射效应对地面目标散射回波的影响。首先构建一个尺寸略大于目标包围盒的粗糙地面实体模型;然后结合“镜像法”改进射线追踪技术,分析电磁波在目标各部件间、目标同实体地面之间以及同虚拟半空间分界面之间的射线传播过程;最后结合高频渐近方法完成电磁散射计算。利用精确数值法计算结果对所提出技术进行了验证,并将其应用于地面目标的SAR图像高逼真度仿真,同实测SAR图像比对表明了所提技术具有良好的适用性。The conventional shooting and bouncing ray(SBR)technique is mainly applied to electromagnetic(EM)scattering calculation for targets in the context of the free-space.When it is used for the EM scattering computation and SAR image simulation for the complex targets on rough ground surfaces,the calculation error increases especially at small grazing angles.To address the above problem,an improved SBR technique based on the four-path model is proposed,where the multiple reflections as well as the multipath scattering contributing to the total scattered field of integrated target-ground scene are taken into account.The integrated scene consists of the geometric models for the given target and its underneath rough ground slightly larger than the bounding box of target is firstly constructed.Next,the interaction scattering among target,ground geometry and the half-space interface is analyzed by the combination of the improved ray tracing technique and the quasi-image method.The scattering contribution for ray tubes is finally calculated using conventional high-frequency asymptotic methods.Results calculated by numerical method are used to validate the proposed technique.Simulated SAR images for typical targets on rough ground surface are presented and compared with the measured counterparts to demonstrate the usefulness of the proposed technique in high-fidelity SAR images.

关 键 词：电磁散射 合成孔径雷达(SAR) 地面目标 弹跳射线(SBR)技术 “四路径”模型 

分 类 号：TN011[电子电信—物理电子学]