基于信号稀疏表示的多频多极化雷达目标信号相干融合成像技术

Radar target recognition is an important problem needed to be solved urgently for modern radar. The combination of high resolution and full polarization is considered as the one of the most promising approach to solve the problem, and thus high-resolution fully polarimetric imaging radar is also becoming an important direction of modern radar development. However, it is known that the performance of traditional high-resolution fully polarimetric radar imaging system is restricted by the technical merit and price. In this project, multi-frequency multi-polarimetric SAR/ISAR (MFMP-SAR/ISAR) signal level fusion imaging technology based on sparse observations from frequency and polarimetric domain are proposed. It aims at remarkably improving the estimation precision of scattering center polarimetric parameters and the resolution of radar imaging through the coherent fusion of the radar sparse observations information. Intrinsically speaking, MFMP-SAR/ISAR imaging is one kind of signal sparse representation under incomplete measurement. Based on the signal sparse representation theory, this project will study some basic problems and imaging algorithms in MFMP signal level fusion processing, including the theoretic frame, sparse modeling through data analysis and mechanism analysis, amplitude-phase compensation, high resolution two-dimensional signal fusion imaging, and performance analysis and optimization of system design. The ultimate purposes of the above study are to explore future new kind of wideband high-resolution fully polarimetric radar system and to improve fusing performance of present multi-dimensional MFMP-SAR data.

极化雷达成像技术有机综合了高分辨成像和全极化测量的优点，非常适合用于对人造目标的精细刻画，对雷达目标识别具有特别重要的意义。传统极化雷达成像受制造工艺、成本及宽带极化测量体制不完善等约束，探测性能进一步提升的空间有限。本项目提出基于信号稀疏表示的多频多极化雷达目标信号相干融合成像技术，利用多源相干数据的信号层融合，预期显著提升成像系统空间分辨率和全极化散射中心参数估计精度，增强目标可检测和识别的特征，为目标提取和结构反演奠定有力基础。项目将多频多极化信号相干融合成像表述为可稀疏表示的不完全测量问题，基于信号稀疏表示理论，重点研究多频多极化稀疏观测建模、极化-频率-角度联和域目标特性增强的稀疏表示寻优融合成像、融合性能评估及基于多维波形编码的系统优化设计等。力争探索我国全极化宽带成像雷达多维波形编码新体制，并显著改善已有多频段极化成像雷达的综合性能，同时促进极化雷达和稀疏微波成像理论的发展。

极化雷达成像技术有机综合了高分辨成像和全极化测量的优点，非常适合用于对人造目标的精细刻画，对雷达目标识别具有特别重要的意义。传统极化雷达成像受制造工艺、成本及宽带极化测量体制等约束，探测性能进一步提升的空间有限。本项目提出基于信号稀疏表示的多频多极化成像雷达（MFMP-SAR/ISAR）目标信号相干融合成像技术，将信号相干融合成像表述为可稀疏表示的不完全测量问题，基于信号稀疏表示理论，建立了目标散射特性的多频相干极化模型和多频极化雷达信号稀疏表示融合模型，提出了考虑大视角测量下雷达视角差异、电离层传播效应下法拉第极化旋转等实际因素的相干配准预处理方法和联合域目标增强融合成像处理方法；建立了基于相关性度量的融合性能评估方法和指标，应用多维波形编码多自由度灵活发射策略，实现了基于多维波形编码的MFMP-SAR/ISAR系统方案设计和基于OFDM-Chirp波形的优化改进；建立了数字仿真系统，设计并完成了微波暗室实验，通过数学仿真、暗室试验和实测数据处理，验证了MFMP-SAR/ISAR极化高分辨融合成像性能，显著提升了空间分辨能力和全极化散射中心参数估计精度，可用于增强目标可检测和识别的特征，为目标提取和结构反演奠定有力基础。项目成果为探索全极化宽带成像雷达多维波形编码新体制、改善多频段多极化成像雷达的融合性能做出贡献，同时也丰富了当前极化雷达成像、稀疏微波成像的理论研究。