MIMO雷达稀疏目标极化高分辨三维成像研究

The unwelcome effects in traditional 2D imaging radar like overlay, shadow and foreshortening, seriously degrade the performance of radar in target classification and recognition, and it has become an urgent demand to develop polarimetric 3D imaging techniques to enhance the performance of radar in classifying and recognizing sparse targets like buildings and vehicles. This study is dedicated to investigating polarimetric tomographic techniques in terms of array design, signal processing and information processing, in the background of UAV reconnaissance. Firstly, aimed to form a virtual aperture much larger than real aperture in space-constricted platform like UAV, MIMO-array-based techniques will be proposed with consideration of 3D imaging application. Secondly, joint imaging method will be proposed in order to realize high resolution imaging in short baseline condition, accurate estimation of polarimetric information, and motion compensation. Thirdly, techniques for extracting geometrical features are to be proposed by utilizing polarimetric property of targets. At last, simulations and real data experiments are to be done to verify algorithms. The study is of great academic value in establishing signal processing theory for polarimetric tomographic SAR, and is also beneficial in developing polarimetric tomographic radar system.

传统二维成像雷达存在层叠、阴影和收缩等畸变和失真问题，导致雷达对目标分类识别能力严重不足，发展极化高分辨三维成像技术是提升雷达对车辆、建筑物等稀疏目标分类识别能力的迫切需求。本项目立足单航过极化层析三维成像雷达体制，以无人机侦察为主要应用背景，开展极化层析三维成像“阵列设计-信号处理-信息处理”三个层面的研究：针对无人机平台的空间受限特点，面向三维成像应用，基于MIMO阵列技术提出远大于实际阵列的虚拟孔径形成方法，突破阵列尺寸对雷达分辨能力的制约；提出多极化多基线联合三维成像方法，解决短基线条件下的高分辨成像、极化信息的精确估计以及运动补偿难题；提出基于极化散射特性的目标几何结构特征提取技术；开展仿真和实测数据实验验证。本项目的研究对于构建极化层析三维成像信号处理理论体系有重要的学术意义，也可为极化层析三维成像雷达系统的研制提供技术支撑。

本项目以提升雷达对稀疏目标的分类识别能力为目标，以无人机侦察为主要应用背景，从“波形设计-信号处理-信息处理”三个层面开展了MIMO雷达稀疏目标极化高分辨三维成像研究，初步建立了极化层析高分辨三维成像信号处理理论体系，提出了稀疏目标极化高分辨三维散射特征提取方法，开展了仿真和实测数据实验验证。研究成果包括：（1）针对战场侦察对小型人造目标的高分辨三维精细成像识别需求，提出超短基线下的极化层析三维成像方法，实现对车辆等小型人造目标的亚米级三维高分辨成像；（2）提出了人造目标三维全极化散射特征提取方法，实现人造目标典型结构、三维尺寸等特征参数的精细反演；（3）提出了基于正交编码信号的DBF-MIMO-SAR成像方法，有效提升MIMO-SAR波形隔离性能，可应用于MIMO-SAR分布目标成像。研究成果有望在城区测绘、战场侦察等领域取得重要应用。项目开展期间，发表EI论文5篇，出版专著1部，专利5项。培养博士生4名，硕士生1名。