基于频率分集阵列星载广域监视雷达的关键技术研究

The spaceborne wide-swath surveillance radar is able to provide high-resolution wide-swath synthetic aperture radar (SAR) image for the region of interest, and it can also detect and estimate the parameters of the moving targets, thus it has important application value in the fields of environment monitoring and battlefield reconnaissance. And how to effectively utilize the limited channel resources on the satellite to further improve the system performance has been an important research direction in the field of synthetic aperture radar. Frequency diverse array introduces a small frequency increment between the element-transmitted signals, which makes the antenna transmission pattern is range-angle dependent, and it brings many advantages for the radar design. Focusing on the spaceborne synthetic aperture radar ground moving target indication system based on frequency diverse array, this project firstly optimize the array parameters, then studies the clutter suppression method of ambiguous SAR echoes, and explores the deceptive scene interference suppression method for multi-channel SAR; lastly, the main error sources of the system are modeled and analyzed, and the corresponding calibration and compensation method are explored. This research not only promotes the development of the theoretical model of frequency diverse array, but also provides a new idea to enhance the imaging and detection performance of spaceborne surveillance radar.

星载广域监视雷达可以对感兴趣区域进行高分辨率宽测绘带合成孔径雷达成像，并对其中的运动目标进行检测和参数估计，在环境监测和战场侦察等领域具有重要应用价值。如何有效利用星上有限的通道资源进一步提高系统性能是合成孔径雷达领域一个重要的研究方向。频率分集阵列通过对阵元发射信号间引入了一个较小的频率增量，使天线产生同时依赖于距离和角度的发射方向图，为雷达设计带来诸多优势。本项目针对基于频率分集阵列的星载合成孔径雷达地面运动目标检测系统，在对其进行阵列参数优化的基础上，研究模糊回波的杂波抑制方法；探索针对多通道合成孔径雷达的欺骗式场景干扰抑制方法；并对系统几类主要误差源进行建模分析，探索相应的定标和补偿方案。该项研究不仅促进了频率分集阵列理论模型的发展和完善，更为提升星载广域监视雷达在成像和检测等方面的性能提供了新思路。

星载广域监视雷达存在杂波和目标距离模糊难题，频率分集阵天线通过改变发射天线单元之间的载波频率，提供距离维可控自由度，在杂波和目标距离解模糊及对抗欺骗干扰等方面具有很好的应用潜力。本项目针对星载广域监视雷达存在的以上问题及频率分集阵列雷达的特殊优势，开展基于频率分集阵列技术的星载广域监视雷达系统设计和信号处理方法研究。重点针对系统体制、基于频率分集阵列的多输入多输出星载广域监视雷达系统参数设计、广域监视雷达模糊回波杂波抑制、欺骗式干扰抑制方法等方面开展研究。通过本项目的研究工作，初步形成了星载频率分集阵广域监视雷达的基本理论框架，提出了宽幅高分SAR/GMTI实现方案、天基雷达模糊杂波抑制、主瓣抗干扰、杂波特性分析、目标检测等一系列新方法和新技术，并完成系统仿真建模，部分技术实现了在机载校飞试验中的应用；研究成果为未来星载雷达预警探测、星载宽幅高分成像及抗干扰等应用问题提供了新思路。