面向复杂电磁环境的多载波捷变阵列雷达研究

There are strong demands and also significant scientific challenges in radars under complex electromagnetic environments. Frequency agility radar (FAR) has advantages for its high agility in waveforms and high signal-jamming ratio gain, and has been validated as an effective scheme to function under current electromagnetic environments. However, traditional monotone FAR suffers from a bottleneck that the performance severely deteriorates when some pulses are missed. And thus such FAR is difficult to adjust to the future electromagnetic environments with strong interference. The reasons include: radar echoes obtaining incomplete spectral information result in sensitivity to the missing-pulse phenomenon; mismatch problems in target model and deficiencies in current target detection algorithms further worsen the false alarm rate and miss detection rate of targets. To address these problems, it is proposed the idea of multi-carrier agility array radar, and the idea of applying new theories of continuous compressed sensing and hypothesis test for sparse models into exploiting targets’ prior of sparse characters. It is planned to study the target parameter estimation, target detection and waveform optimization problems and so forth...In this project, multi-carrier agility array will be innovated to enhance the robustness against missing-pulse problem. And novel compressed sensing methods based on targets’ prior of sparse characters will be composed to mitigate the deficiencies in parameter estimation accuracy, false alarm and miss detection of targets. Besides, waveform optimization will be invoked to further enhance the radar performance. This project is expected to significantly improve the survivability and detecting capacity of radars under complex electromagnetic environments, and therefore, has important academic value and application prospects.

复杂电磁环境下雷达探测问题军民需求迫切、科学挑战性强。频率捷变雷达具有波形灵活多变、信干比增益高等优势，被证明是应对目前电磁环境的有效手段。但传统单一载波的频率捷变雷达存在性能瓶颈，出现部分脉冲丢失时，探测性能严重下降，难以适应未来强干扰环境威胁。其原因包括：雷达回波频域信息不完整，对脉冲丢失敏感；目标模型失配问题和现有检测算法的性能缺陷，进一步恶化了目标虚警漏检率。针对这些问题，本项目提出多载波捷变阵列雷达，结合连续域压缩感知、稀疏模型检测等新理论，挖掘目标稀疏特征，在目标参数估计、检测、波形优化设计等方面开展研究。.本项目提出多载波捷变阵列波形以提升脉冲丢失情况下的鲁棒性，构造基于目标稀疏先验分布特征的压缩感知算法以弥补现有方法估计精度和虚警漏检方面的不足，开展优化设计波形来进一步提升雷达性能。项目成果将显著提升雷达在复杂电磁环境中的生存和探测能力，具有重要的学术价值和应用前景。

本项目围绕复杂电磁环境下雷达探测问题开展研究：针对敌方对雷达的有意干扰，提出了多载波捷变阵列雷达新体制；针对通信设备造成的无意干扰，提出了多种通信雷达一体化方法。..一、项目较为系统地解决了多载波捷变阵列雷达中的信号模型、处理算法和理论性能边界等问题，具体成果包括：. - 提出了新体制雷达发射和接收方式，推导了回波模型，并给出了目标稀疏重建算法；. - 推导了频率捷变雷达重建目标的近似充要条件。前人基于约束等容性等推导精确稀疏重建的边界条件，但通常过于松弛。项目利用积分几何等工具，推导得到了重建目标近似充要条件的解析表达式，对指导该新体制雷达的系统设计具有重要意义；. - 针对稀疏重建算法难以实时计算的难题，提出了模型和数据联合驱动算法，将雷达模型结构信息嵌入至神经网络中，迭代次数比传统梯度下降类算法降低了1-2个数量级，网络参数规模比纯数据驱动算法降低了1个数量级；. - 与工业部门合作开展了原型样机试验，实测验证了该体制应对复杂多干扰环境的优异性能。..二、在通信雷达一体化这一新兴领域，提出了基于多载波捷变阵列、基于多输入多输出（multiple input multiple output，MIMO）阵列的的多种研究路径，具体包括：. - 巧妙地将多载波捷变阵列与通信索引调制相结合，将通信信息嵌入至频率和天线的选择当中，在几乎不影响雷达性能的同时，提升了通信能力；. - 面向同时多目标探测、多下行用户通信的需求，研究了MIMO阵列一体化波形设计方法，提出多用户通信符号与专用雷达波形联合预编码方法，比仅用通信符号预编码的传统方法，提升了系统空域自由度，保障了多目标覆盖能力；. - 开展了半实物仿真试验，验证了上述路径的有效性。正积极与工业部门合作，计划开展原型样机试验。