SAR成像算法的验证需要相应的回波数据, 同时SAR图像目标识别算法的检验需要大量的SAR图像, 针对这一要求, 提出了一种典型地形SAR回波模拟与图像仿真的方法。首先分析了分形布朗曲面及其水平集的特征。在此基础上, 运用中点位移法生成了描述山脉地形的数字高程数据, 提出了生成海岸地形(“归零法”)及河流沟壑地形(“归零取反法”)的新方法。引入电磁散射模型, 计算了每个分辨单元的后向散射系数。给出了基于二维快速傅立叶变换的SAR回波模拟算法的推导过程及相应的仿真结果, 并对结果进行了分析和讨论, 证明了该方法的正确性。

In order to meet the increasing demand for SAR raw signal and SAR images simulation, a new method for the simulation of the SAR raw signal and images of typical terrains is proposed in this paper. The properties of Fractal Brown Surface and its horizontal are analyzed first. Then the Digital Elevation Model (DEM) of the mountain terrains is generated by the usage of random MPD (Middle Point Displacement) method. The new approaches for the generation of coastal terrain (Return-to-Zero method) and river-ravine terrain (Return-to-Zero-Inversion method) are also proposed. The back scattering coefficient of each resolution cell is calculated by employing the corresponding electromagnetic scattering model. The algorithm of SAR raw signal simulation based on the 2DFFT (two-dimensional Fourier Transform) is presented. The simulation results show that the proposed method is valid.