峡谷型分区域复合粗糙面电磁散射特性研究

提出了一种分区域复合表面模型来描述峡谷环境的天然腔型结构,研究了峡谷型分区域复合粗糙面的电磁散射特性。采用蒙特卡罗方法,利用高斯谱函数模拟峡谷环境的陆地粗糙面,利用Pierson-Moskowitz(PM)海洋谱模拟峡谷的海面部分,交界处运用加权反正切函数平滑处理,建立了峡谷型分区域复合粗糙面模型。考虑到自然环境中峡谷所具备的天然腔型结构,引入射线密度归一化(RDN)思想,采用改进射线弹跳法与物理光学法的混合方法,计算峡谷型分区域复合粗糙面的电磁散射特性。对比了陆地粗糙面、海面和峡谷型分区域复合粗糙面的电磁散射特性,计算了峡谷型分区域复合粗糙面的散射系数,并讨论了峡谷开口范围、陆地粗糙面的均方根高度和相关长度对峡谷型分区域复合粗糙面电磁散射特性的影响。仿真结果对于反演峡谷环境的电磁特性以及遥感、探测具有借鉴意义。

Research on Electromagnetic Scattering Characteristics of Valley Composite Rough Surface

A composite rough surface model is presented for describing the concave structure of valley environment.The electromagnetic scattering characteristics of valley composite random rough surface are studied. Monte Carlo method is used to build valley composite random rough surface, Gauss spectral function is used to simulate ground part of valley, and Pierson Moskowitz (PM) spectral function is used to simulate sea part of valley. Weighted inverse tangent function is presented to smooth adjacent region. The ray density normalization (RDN) theory is introduced to improve the SBR (shooting and bouncing ray) method. In consideration of the inartificial cavity construction of valley in natural environment, the improved SBR/ PO is used to calculate the electromagnetic scattering of the valley composite rough surface. Electromagnetic scattering characteristics of ground, sea and valley composite random rough surface are compared. The impacts of open area of valley concave structure on the curves of bistatic scattering coefficient (BSC) of horizontal-to-horizontal (HH) polarization of valley environment are analyzed. The influences of root mean square (RMS) and correlation length of ground rough surface on BSC of HH polarization are discussed. The numerical results can be used as reference in the fields of remote sensing, detection and inversion of electromagnetic environment.