基于扰动波速散射理论的高分辨率SAR回波信号建模和应用

Wide time-width and bandwidth pulse signals are transmitted in high resolution synthetic aperture radar (SAR) systems for high range resolution. But the narrow-bandwidth signal condition, which is the base of the current echo signal models and imaging algorithms, is not satisfied, and the echo signal models and the corresponding algorithms are becoming one of the technical bottlenecks for improving SAR image quality of wide and width and ultra wide-bandwidth SAR systems. So the more precise echo model and imaging algorithms should be derived from the basic theory. This project plans to derive the radar scatter field model of targets' scattering function according to the perturbated wave speed scattering theory and the partial differential Maxwell's equations method. The radar echo signal expressions for wide and ultra-wide SAR are derived, and the general imaging operators are investigated to construct the scattering function according to the formal adjoint operator theory. Based on the echo model and the imaging operation, optimization algorithm, which Synthesizes the high accurate echo signal model and the core of the classic image information algrithm, for wide and ultra-wide high resolution application is presented. The signal echo model and imaging algorithm based on the perturbated wave speed scattering theory will improve the accurance and universal ablity of the current model, and supply theoretical base and technical support for improving the image quality of high resolution SAR.

高分辨率合成孔径雷达（SAR）需要发射大时宽、宽频带的脉冲信号来实现距离向的高分辨，SAR 回波信号模型及成像算法的窄带前提不再适用，信号模型问题已经成为宽带/超宽带高分SAR 系统图像质量提升的技术瓶颈之一，因此亟待回归基础理论，深入研究更为精确的回波信号模型和成像处理算法。本项目基于波速扰动散射理论，利用标量麦克斯韦偏微分方程工具，研究目标散射函数对应的散射场，推导适用于宽带/超宽带高分辨率 SAR的高精度通用 SAR 回波信号模型，并研究基于形式伴随算子理论的目标散射函数的重构方法。在此基础上针对宽带/超宽带高分辨率SAR应用，提出综合高精度回波信号模型与经典成像算法思想的优化改进算法。本项目提出的高精度通用SAR回波信号模型和成像反演算法将改善现有模型的精度和通用性，为提升高分辨率SAR图像质量提供理论基础和技术支撑。

高分辨率合成孔径雷达（SAR）需要发射大时宽、宽频带的脉冲信号来实现距离向的高分辨，SAR 回波信号模型及成像算法的窄带前提不再适用，因此需要从基础理论出发，深入研究更为精确的回波信号模型和成像处理算法。本项目基于波速扰动散射理论，通过研究基于偏微分Maxwell 方程的回波信号散射场以及高精度回波信号模型，综合考虑散射机理、平台运动、宽带天线等诸多复杂因素，求得了偏微分Maxwell方程的通用解，并结合实际应用需求，总结本项目信号模型的适用性条件。在此超宽带发射信号的回波信号模型的基础上，研究了通用SAR成像算法，实现了基于压缩感知的SAR 成像，最后基于PDEs 逆投影滤波算子实现了图像处理与成像聚焦的综合。本项目的研究成果为高分辨率SAR成像方法提供理论支撑和工程参考。