Signals of Opportunity Reflectometry (SoOp-R) employs the communication system, GNSS (Global Navigation Satellite System) constellation and other potential Signals of Opportunity (SoOp) as the transmitters. In recent years, it has gained increased interests. Several experiments have been carried out, however it is still in the initial development stage. Theoretical predictions of SoOp Reflectometry for land surface parameters detection, such as soil moisture and vegetation biomass, should be carried out simultaneously. Meanwhile, at present less works are paid attention to the polarization study of the polarizations. The first-order radiative transfer equation models are employed here and they are developed according to the wave synthesis technique to get the various polarization combinations. Using the two models as analysis tools, we simulate the bistatic scattering at all potential SoOp Reflectometry bands, i.e., P-, L-, C- and X-band for circular polarizations and linear polarizations. While the original commonly used microwave scattering models are linear polarizations, here we compare the difference. Although the models can simulate bistatic scattering at any incident angles and scattering angles. Four special observation geometry are taken into considerations during the analysis. Using the developed models as tools, the developed models establish the relationship between the land surface parameters (such as soil moisture, soil roughness and vegetation water content, diameters et al.) and bistatic radar cross section. The forward scattering models developed here enables the understanding of the effects of different geophysical parameters and transmitter–receiver observation scenarios on the bisatic scattering at any polarization combinations for any potential SoOP reflectometry bands. Robust retrieval methods for soil moisture and vegetation biomass can benefit from the forward scattering models.

中文翻译：

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机会反射法信号在陆地表面圆极化和线极化的双基地散射模拟

机会反射法（SoOp-R）使用通信系统，GNSS（全球导航卫星系统）星座和其他潜在机会信号（SoOp）作为发送器。近年来，它获得了越来越多的兴趣。已经进行了几次实验，但是它仍处于初始开发阶段。SoOp反射法用于土地表面参数检测（例如土壤水分和植被生物量）的理论预测应同时进行。同时，目前对极化的极化研究较少。这里采用一阶辐射传递方程模型，并根据波合成技术对其进行了开发，以获得各种偏振组合。使用这两个模型作为分析工具，我们在圆偏振和线性偏振的所有潜在SoOp反射测量波段（即P，L，C和X波段）上模拟双基地散射。虽然最初常用的微波散射模型是线性极化，但在这里我们比较差异。尽管模型可以模拟任何入射角和散射角的双基地散射。在分析过程中会考虑四种特殊的观察几何形状。使用开发的模型作为工具，开发的模型建立了陆地表面参数（例如土壤湿度，土壤粗糙度和植被含水量，直径等）与双基地雷达横截面之间的关系。在此开发的前向散射模型使您能够了解不同的地球物理参数和发射器-接收器观察方案对任何潜在SoOP反射谱带在任何偏振组合下双散射的影响。土壤水分和植被生物量的稳健检索方法可以从正向散射模型中受益。