近地空间目标全极化高分辨雷达成像中的波形设计及信号处理相关技术研究

The safety of aerospace facilities is threatened by the near earth object (a.k.a. NEO). The most important means to guard the safety under this threat is the disaster warning through imaging, recognizing and tracking of the NEO by using microwave remote sensing. Since NEO is distant, speedy and similarly sized, to recognize NEO requires as more information as possible. Among all the potential ways, full-polarized high-resolution imaging is considered as the most efficient one. However the full-polarized high-resolution imaging of NEO brings some extra difficulties, including: 1. instantaneous full-polarization radar system is requested, which is difficult to realize; 2. instantaneous ultra-wideband waveform with absolute isolation between the orthogonal polarizations and low side-lobe is required, which is difficult to design; 3. the polarization information should be fully used, which is difficult to process. To resolve these 3 demanding requests, the waveform design and the signal processing techniques for the full-polarized high-resolution radar imaging of NEO is researched. During the researching, the waveform design and signal processing will be studied simultaneously, the full-polarization information processing and super resolution imaging algorithm will be combined. The research is focused on the analysis of full-polarization scattering characteristics of NEO, the novel waveform design of full-polarization imaging radar, the full-polarization super resolution imaging and the calibration techniques. The technical support for the radar recognition of NEO is hopefully provided by these studies.

近地空间目标对我国航天安全构成很大威胁，当前利用雷达对其成像识别后按威胁等级进行跟踪预警，是减少灾害的重要手段。近地空间目标距离远、速度快、尺寸相近，识别中需依靠尽可能多的特征信息，全极化高分辨成像被普遍认为是提高雷达目标识别能力的重要手段，但近地空间目标全极化高分辨成像的技术难度较大，主要表现在：①要求采用同时全极化体制，系统实现难度大；②要求发射全带宽高隔离度、低副瓣的瞬时大带宽波形，波形设计难度大；③要求充分利用目标全极化回波信息，信号处理难度大。本项目针对“三大难题”，从新波形设计和信号处理两方面同时着手，将极化信息处理和超分辨成像算法相结合，开展近地空间目标全极化高分辨成像中的波形设计及信号处理相关技术专门研究，重点围绕近地空间目标全极化散射特性分析、雷达发射波形设计、全极化超分辨成像算法及误差校准方法四方面开展研究，为近地空间目标遥感识别和安全预警提供技术支撑。

本项目以近地空间目标探测为背景，研究了高速微动目标的全极化ISAR超分辨成像相关技术。主要研究成果包括：首先，分析了空间目标的微多普勒特性，研究了基于滑动型散射中心的空间微动目标电磁散射模型，给出了目标的全极化回波仿真生成方法。之后， 研究了同时具有较好极化测量性能和距离分辨率的波形超低旁瓣非线性调频波形，提出了具有很好隔离度的同时全极化宽带测量波形。然后，研究全极化散射中心参数估计方法（简称P-MUSIC方法），研究了基于CP-GTD模型的极化ISAR超分辨成像算法。最后，提出了阵元互耦补偿的阵列有源方向图合成方法，以及基于极化补偿的双极化平面阵列波束形成方法，给出了基于全方向图校正法的极化相控阵极化测量误差校准方法。.上述研究为近地空间目标全极化雷达探测和全极化雷达成像提供了技术基础。