多次散射中心横向位置属性及图像表征

多次散射结构是不可忽视的重要散射来源，其等效视在散射中心往往偏离目标区域，目前的解译和识别方法不具备对SAR图像中的多次散射中心现象进行散射机理和散射结构溯源的能力。为深入挖掘多次散射中心位置的本质，本文以散射中心的理论为基础，正向建立了具有明确物理含义的散射中心模型，揭示了多次散射中心横向位置与复杂多次射线路径的联系，解释了多普勒频率的形成机制，并探讨了其在雷达目标识别中的应用。首先，本文从电磁散射物理过程出发，推导了任意阶次射线场的解析表达式；其次，结合正向物理推导获取的雷达回波信号表达式与逆傅里叶变换，表征了目标在单站雷达上的图像特征，实现了散射中心三维空间位置在单站雷达图像中的直接映射；最后，通过仿真，构建了多次散射射线光程、回波信号相位表征、雷达图像散射中心位置三者之间的物理关联。

Lateral Position Properties and Image Representation of Multiple Scattering Centers

The multiple scattering structure is an important scattering source that cannot be ignored, and its equivalent apparent scattering center often deviates from the target area. The current interpretation and recognition methods do not have the ability to trace back the scattering mechanism and scattering structure of the multiple scattering center phenomenon in SAR images. In order to dig deeper into the nature of the multiple scattering center position, in this paper, a scattering center model with clear physical meaning based on the theory of scattering center is established, the connection between the lateral position of the multiple scattering center and the complex multiple ray paths is revealed, the formation mechanism of Doppler frequency is explained, and its application in radar target recognition is explored. Firstly, the analytical expression of ray field with arbitrary order is derived based on the physical process of electromagnetic scattering. Secondly, combined with the radar echo signal expression obtained from forward physical derivation and the inverse Fourier transform, the image characteristics of the target on the monostatic radar are characterized, and the direct mapping for the three?dimensional spatial position of the scattering center in the monostatic radar image is realized. Finally, the physical correlation between the multiple scattering ray paths, the phase characterization of the echo signal, and the position of the scattering center in the radar image are constructed by simulation.