不同类型土壤地面与其上方目标散射特性研究

针对超低空目标与地面复合电磁散射的问题,以某型巡航导弹作为超低空目标的典型代表,研究了不同类型土壤地面与其上方巡航导弹的散射特性。在考虑不同类型土壤组成成分的基础上,采用四成分土壤介电模型计算其介电常数,分析了土壤介电常数与土壤类型和土壤湿度的关系;以二维高斯粗糙面模拟地面环境,引入锥形入射波克服粗糙面的边缘衍射,应用基于物理意义的双网格法(Physics Based Two Grid, PBTG)结合稀疏矩阵规范网格法(Sparse Matrix Canonical Grid, SMCG)仿真分析了土壤类型、入射波频率与极化等因素对地面环境电磁散射特性的影响;基于目标与环境的复合表面积分方程,研究了不同类型土壤地面与巡航导弹的复合散射特性。分析表明:巡航导弹与粗糙面相互作用,使三种类型土壤地面的散射系数均有所增大。研究成果为不同类型土壤地面环境遥感探测及其上方超低空目标的探测提供了理论参考。

Research on EM Scattering Characteristics of Rough Surface in Different Types of Soil and Target

To solve the problem of the composite electromagnetic scattering from super-low altitude target on the earth surface, the cruise missile is regarded as the typical example of super-low altitude target. The scattering characteristics of earth surface in different types of soil and cruise missile are analyzed. Considering the ingredient of different types of soil, the permittivity of it is calculated by using four component models. And the relationships between the permittivity and the soil components and moisture are analyzed. The 2D Gaussian rough surface model is generated to simulate the real earth surface. The tapered incident wave is applied to eliminate the edge diffraction. The effects of soil components, the frequency and polarization of the incident wave on the earth surface scattering characteristics are analyzed by using PBTG/ SMCG algorithm. Based on the surface integral equation on scattering between target and environment, the composite electromagnetic scattering from cruise missile and different types of soil rough surface is analyzed. The analysis shows that the mutual effects between the cruise missile and the rough surface result in the increase of the scattering coefficient of the three types of soil rough surface. The results of this paper have a theoretical support for different types of soil rough surface remote sensing and super-low altitude target detecting.