空间目标多弧段干涉三维ISAR成像技术研究

Interferometric inverse synthetic aperture radar (InISAR) imaging is a promising technique and has received much attention, which can provide the three dimensional images for target recognition. This project mainly focuses on three dimensional interferometric ISAR imaging of space objects based on multiple observed arcs data, and makes an intensive study as follows: Firstly, it will built an effective interferometric ISAR imaging model according to the relative motion between the space object and the radar. Then the strategy for the optimal interferometric arcs selection is provided based on the requirement of image resolution, signal to noise ratio and so on. Secondly, the interferometric phase error results from the data processor will be analyzed, and a phase compensation method will be proposed. Thirdly, according to the principle of radar imaging, the characteristics of ISAR images and the reseasons for the mismatch among images will be analyzed. Then, an ISAR image registration method with high efficiency will be provided by studying the principle of optical image registration. Finally, interferometric phase unwrapping method will be researched by using the combination of different baselines with multiple arcs. Overall, a three dimensional interferometric ISAR imaging algorithm based on multiple arcs for space targets will be proposed.

干涉式逆合成孔径雷达成像是一种将干涉技术与逆合成孔径雷达（ISAR）技术相结合的成像方法，可用于对空间目标进行三维成像，以获得其结构特征，是一种有效的空间目标识别手段。本项目将紧密围绕多弧段干涉体制下的空间目标三维ISAR成像方法展开深入研究：首先，根据空间目标与雷达之间的相对运动，构建精确的空间目标多弧段干涉成像模型，综合考虑成像分辨率、系统信噪比以及目标姿态变化等因素的影响，确定弧段选择方法；其次，分析二维成像处理中的平动补偿、越分辨单元徙动校正以及方位向聚焦算法等处理环节对干涉相位的影响，提出相应改进措施；再次，根据雷达成像原理分析ISAR图像特点以及失配原因，以光学图像配准原理为参考，研究高效的ISAR图像配准方法；最后，通过对空间目标干涉成像的参数进行约束，研究利用多弧段实现长短基线组合的干涉相位解缠绕方法，获得完整的空间目标多弧段干涉三维成像算法。

随着航空航天技术的发展，空间目标的数量迅速增加，对空间目标进行探测、识别与监视，实时掌握空间态势，在维护国家的空间安全和利益方面具有重要意义。逆合成孔径雷达（Inverse Synthetic Aperture Radar，ISAR）对空间目标进行高分辨成像，获取其结构姿态信息，为空间目标的分类、识别和故障诊断等应用提供重要的依据。本项目从干涉模型设计、高质量成像、图像配准和相位解缠绕等方面对多弧段空间目标干涉三维ISAR成像技术进行研究。根据ISAR成像观测几何，构建空间目标多弧段干涉模型，推导高度计算函数，分析干涉性能；提出基于广义Keystone的高质量ISAR成像技术，解决非匀速转动空间目标越分辨单元徙动引起的图像散焦；针对低信噪比下的ISAR图像配准和散射点关联，提出基于强点拓扑信息的图像配准方法，并利用相邻弧段的相关性在连续多弧段模式下实现散射点关联；提出基于多弧段的干涉相位解缠绕方法，利用不同弧段间隔带来的多基线效应，结合散射点的二维定标信息，准确估计各散射点干涉相位的模糊倍数，获得高质量的InISAR三维像。