微起伏地面的建筑物后向散射特性研究

针对包围城市建筑物地面起伏较小的情况,解析推导了建筑物后向散射结果。后向散射主要由建筑物屋顶、墙面以及地面的一次散射和地面、墙面形成的二面角的二次散射组成,利用微扰法计算一次散射,对于二次散射,墙面利用几何光学法,地面利用微扰法计算。数值分析了后向散射和主要场景参数之间的变化关系,例如建筑物方位角、电磁波入射角、地面和墙面的介电常数和地面粗糙度,为城市目标SAR图像解译和建筑物参数反演提供了一定理论指导。

Research on Backscattering from Buildings Surrounded by Slightly Rough Ground

In order to analytically evaluate the backscattering from buildings in closed form,a simplified building is placed on a moderately rough ground.The backscattering can be decomposed into single-scattering from the building roof,the vertical walls and rough ground and double-scattering from the dihedral formed by vertical walls and ground.The single-scattering contributions are evaluated by using small perturbation approximation (SPA).For double-scattering,the geometrical optics (GO) is used to evaluate the field reflected by the wall,and SPA to evaluate the field scattered by the ground.Finally,the above model is used to analyze the relationship between the backscattering and the scene parameters,such as the orientation of the building,the incident angle of electromagnetic wave,the dielectric of the wall and ground,the roughness of the ground.This model can be used as theory guidance of the interpretation of SAR image of urban structures or the inversion of parameters of buildings.