随机粗糙地表的双尺度微波散射模型研究  

Research on Microwave Two-Scale Scattering Model for Conducting Random Rough Surface

作　　者：余凡[1] 赵英时[1] 沈心一[2] 

机构地区：[1]中国科学院研究生院资源与环境学院,北京100049 [2]北京大学地理信息系统与遥感应用研究所,北京100871

出　　处：《中国矿业大学学报》2010年第3期459-464,共6页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展计划(973)项目(2007CB714407)

摘　　要：通过对复杂双尺度自然地表的研究,提出一种新的双尺度(MTSM)粗糙度地表微波散射模型,采用小波包变换的方法将面上的粗糙度(z(x,y))变换到频域进行处理,粗糙度频谱的低频部分代表大尺度分量,高频部分代表小尺度分量,分别用基尔霍夫近似和小扰动模型来模拟大小尺度的粗糙度,考虑到小尺度的粗糙度是叠于大尺度粗糙度之上,模型在计算小尺度粗糙度的后向散射贡献时还考虑了大尺度起伏造成的几何倾斜.MTSM的解为大尺度粗糙度的基尔霍夫解加上几何倾斜修正后的小尺度粗糙度的小扰动解.采用改进的积分方程模型(AIEM)对MTSM做了初步的验证,结果表明:在入射角θi<30°,粗糙度较小(kσ=0.586 cm)的时候,MTSM有比较好的精度.By the research of the two-scale rough surface, a modified two-scale microwave scattering model（MTSM） was presented to describe the scattering coefficient of typical two-scale rough surface. The roughness function （z（x,y）） is transformed to frequency region by wavelet packet transform, where the low frequency implies the large-scale roughness, as the high frequency refers to the small-scale roughness. Then, the Kirchhoff Approach and Small Perturba- tion Method were used to calculate the backscatter coefficient of the large-scale and small-scale roughness respectively. Considering that the small-scale roughness is overlapped on the large- scale roughness in the two-sale model, the tilting effect caused by the large-scale roughness must be taken into account when we calculate the backscatter coefficient of the small-scale. The output of the MTSM is the sum of the backscatter coefficient of the two scale roughness surface. Finally the advanced integral equation model （AIEM） is used to validate the availability and accuracy of the MTSM. The results show that the MTSM has an acceptable precision when incident angle is less than 30°（θi〈30°） , and the roughness is small（ka=0. 586 cm）.

关 键 词：双尺度 微波散射模型 小波包变换 粗糙度 AIEM 

分 类 号：TP722.6[自动化与计算机技术—检测技术与自动化装置]