电磁涡旋雷达合成孔径三维成像方法

The mode multiplexing of the electromagnetic vortex wave can provide the two-dimensional range-azimuth information, which is superior to the traditional plane wave for the radar imaging community. In the current generation scheme of vortex wave, there exists one bottleneck, which is the radiant energy divergence and results in the obstacles to the electromagnetic vortex radar applications. Based on the waveform diversity theory, this project researches the generation method of the energy-converging beam containing multiple modes, subject to the constraints of the beam divergence on the electromagnetic vortex radar applications. Based on this, by combining the synthetic aperture radar with the vortex wave, a novel three-dimensional imaging radar system is proposed. Focusing on it, this project aims at the range-azimuth real-aperture imaging, the two-dimensional azimuth joint-detection, the motion compensation and the autofocus algorithms, for achieving the three-dimensional imaging. In addition, based on the compressed sensing theory, the project studies the cases with the vortex mode sparsely sampled, by deriving the reduced-order observation signal model and optimizing the sparse-target reconstruction algorithm, and achieves the three-dimensional super-resolution imaging. The achievements of this project can effectively improve the performance of the three-dimensional radar imaging technique, in terms of the resolution, timeliness and system complexity, etc. Besides, the achievements can be applied to other applications of the radar imaging, target recognition, anti-jamming, and various communication systems as well.

多模态复用的涡旋电磁波可直接提供距离-方位角二维信息，在雷达成像领域比传统平面波更具优势。现有的涡旋波生成方案中存在波束能量发散难题，导致涡旋波雷达的应用存在困难。本项目将结合波形分集阵列雷达理论，研究多模态复用的能量聚合型涡旋波束生成方法，解决长期制约涡旋波雷达应用的波束能量发散的难题，在此基础上提出涡旋波与合成孔径雷达相结合的雷达三维成像体制。基于该体制，本项目还将重点研究距离-方位角实孔径成像、方位二维联合检测、精确运动补偿及自聚焦算法，实现场景目标三维成像；并进一步基于压缩感知理论，研究涡旋波模态稀疏时的降维观测信号建模与目标稀疏重构方法，实现三维超分辨成像。研究成果将有效提高雷达三维成像技术的分辨率、时效性等性能，降低系统复杂度，并可推广到其他雷达成像、目标识别、抗干扰以及各类通信系统应用中。

多模态复用的涡旋电磁波可直接提供距离-方位角二维信息，在雷达成像领域比传统平面波更具优势。本项目针对电磁涡旋新型雷达成像体制，力求解决高性能前视成像与目标三维成像问题，其难点在于涡旋波束的能量发散、多模态难以同时复用、电磁涡旋合成孔径成像目标散射点三维精确聚焦、模态欠采样条件下的超分辨成像处理等问题。本项目重点完成了聚束型涡旋波机理研究与方案实现、电磁涡旋合成孔径雷达三维成像与基于稀疏贝叶斯理论的目标三维重构等研究内容，并进一步开展了电磁涡旋雷达成像实验系统的搭建与试验验证；解决了涡旋波束能量发散、目标散射点三维精确聚焦、稀疏模态观测下的超分辨处理等关键问题；取得了聚束型涡旋波雷达全新理论模型、电磁涡旋雷达目标成像性能分析模型、电磁涡旋快拍式二维成像、合成孔径三维成像算法、基于稀疏贝叶斯理论的目标三维重构算法等技术成果，以及论文、专利、项目报告等成果形式，达到了试验系统中心频率35G、合成带宽2G、同时多模态数≥11、解决传统涡旋波发射波束能量扩散问题、成像分辨率在同等孔径下2 倍优于平面波成像性能等性能优势。在以上研究中，电磁涡旋快拍式二维与合成孔径三维成像成果有望在无人平台环境感知与弹载雷达精确制导方面得到应用。聚束型涡旋波雷达系统可作为特殊工作模式，兼容于环形数字阵列雷达。