SAR图像模拟技术被广泛应用于SAR系统的设计和验证、SAR图像的正射纠正、雷达图像解译和目标识别等。随着星载SAR的发展,必然面临着对星载SAR图像模拟的大量需求。本文首先从SAR图像的几何特征和辐射特征出发,探讨了SAR图像模拟技术的原理,分析了RD（Rang Doppler）模型,后向散射模型和斑噪模型。在传统RD模型的基础上,根据不同地形特征（起伏地形和平坦地形）考虑不同的后向散射模型。特别强调了在平坦地形情况下,需要地物分类数据的参与,并利用Ulaby和Dobson的后向散射模型。另外,在SAR图像统计特征的基础上,进行SAR图像的乘性噪声模拟,可以满足更逼真的SAR场景需求。然后,给出了图像模拟的算法流程,并对关键步骤的算法做了分析。最后,在实现基于图像特征的星载SAR图像场景模拟算法的基础上,选择新疆窝依牙地区和天津地区分别进行起伏地形和平坦地形的模拟试验,实验结果证明了本文模拟算法的有效性。

SAR(Synthetic Aperture Radar) image simulation has been widely applied in designing and testifying SAR system,SAR image ortho-correction,Radar image interpretation and target recognition and so on.With the development of space-borne SAR,a large amount of needs for space-borne SAR image simulation will arise.This paper firstly discusses the rationale of SAR image simulation from geometric and radiometric characteristics of SAR image,such as Range Doppler(RD) model,backscattering model,and speckle model.Based on the conventional RD model,different backscattering models are applied to simulation for different topographic characteristics,such as alpine terrain or flat terrain.Especially,the need for land cover data is emphasized in the case of flat terrain and Ulaby-Dobson's backscattering model is used.Besides,speckle simulation is discussed based on SAR image statistical characteristics in order to obtain more realistic SAR image.Then the flow of algorithm is given and several key steps are analyzed.This paper realizes the algorithm of space-borne SAR scene image simulation based on image characteristics.By using the algorithm,tests are performed on alpine terrain in Xinjiang and flat terrain in Tianjin.The results prove the efficiency and validity of the algorithm.