复杂背景下高频地波雷达杂波感知及抑制技术研究

As the Belt and Road and ocean development strategy proposed, monitoring the Exclusive Economic Zone (EEZ) in real-time is an urgent need. High Frequency Surface Wave Radar (HFSWR) is an important equipment for safeguarding the maritime rights and interests depending on the abilities of target detection and ocean remote sensing over the horizon. However, ionospheric clutter which is a special clutter in HFSWR can reduce the performance of HFSWR due to the features of time varying and nonhomogeneous. In this case, how to suppress the ionospheric clutter efficiently is a tough nut for the development of HFSWR. In this project, aiming at improving the ability of ionospheric clutter suppression, two researches are launched here: research on clutter characteristics analysis and separating technique for complex environment, research on ionospheric clutter suppression technique for nonhomogeneous environment. In detail, Signal processing is extended from one-dimension to two-dimension and three new techniques is proposed: clutter separated technique based on sparse recovery, two-dimensional joint clutter suppression based on sub-space based characteristics analysis, secondary data recursion and classified weighted technique for limited secondary data condition. The proposed techniques will be verified in theory and by actual HFSWR data and they will provide the valuable improvement for actual HFSWR system.

随着国家“一带一路”以及海洋发展战略的推进，迫切需要对海洋专属经济区进行实时监测。高频地波雷达具备超视距目标探测及海态监测能力，是保障我国海洋权益的重要手段。但是实际环境中高频地波雷达特有的电离层杂波严重影响了高频地波雷达的超视距探测性能。由于其时变和非平稳的特性，如何有效的对电离层杂波进行抑制一直是制约高频地波雷达发展的难题。本项目针对高频地波雷达电离层杂波抑制的难题，开展复杂背景下的杂波分析及分离技术、复杂电离层杂波背景下的杂波抑制技术等方面的研究。将一维信号处理方法扩展为二维联合信号处理方法，提出基于稀疏恢复的杂波分离技术、基于子空间特性分析的杂波二维联合抑制技术和有限样本条件下的样本递推扩展及分类加权技术。利用理论仿真和实测数据对提出的方法进行验证，从而有效提升高频地波雷达的电离层杂波抑制能力。

高频地波超视距雷达利用垂直极化电磁波能够沿海面绕射传播的特点实现对海面目标及低空飞行目标的超视距探测。其工作在3~30MHz的HF波段，使具有隐身设计的目标无所遁形。其探测距离远、范围广、可全天候工作的特点吸引了众多国家投入大量精力进行高频地波超视距雷达的研制工作。高频地波超视距雷达由于其自身体制的特点以及工作的频段十分拥挤，其面临的杂波及干扰背景是极其复杂的。因此高频地波超视距雷达中的杂波及干扰抑制方法一直是各国学者和科研人员研究的重点问题。.本文针对高频地波超视距雷达，从杂波及干扰特性角度出发，致力于更深入的研究高频地波超视距雷达所面临的杂波及干扰的特点，提出了基于稀疏恢复的杂波相关性分析方法。可在单次快拍条件下，对杂波分量进行分离。基于对电离层杂波角度-多普勒频率二维谱分布特点的分析，提出了基于空时自适应处理方法的多维联合杂波及干扰抑制方法。结合对高频地波雷达中的系统自由度和杂波自由度的分析，提出了局部处理单元大小的确定准则。结合杂波相关性的分析，提出了样本选择和样本扩展方法，提高了对电离层杂波和流星余迹的抑制能力。