复杂电磁环境中基于共形阵列的信号参数估计研究

In recent years, with the development of high-power microwave technology and the application of high-power microwave weapons in electronic warfare, the strong electromagnetic interference radiated by high-power microwave sources causes the spatial resolution capability of passive radar seeker (PRS) to decline sharply. However, the antenna polarization of strong electromagnetic interference is not completely the same as the antenna polarization of the real target. Therefore, the DOA and polarization parameters estimation performance of the PRS can be improved by sensing the polarization difference between the target and the interference. In this project we intend to use conformal polarization reconfigurable antenna array to improve parameters estimation performance of the PRS. Firstly, we intend to analyze the statistics of spatial spectrum of strong and weak signals in order to reveal the mechanism that strong signals lead to parameter estimation degradation of weak signal; Secondly, the optimization method of polarization perception of conformal polarization reconfigurable antenna array is investigated, and the parameters estimation methods of incident signal when strong and weak signals coexist is studied to improve the performance of weak signal parameters estimation; Finally, the influence of the electromagnetic characteristics of the conformal polarization reconfigurable antenna and the array on the parameters estimation of proposed methods is analyzed. The antenna and the array are optimized from the perspective of improving the performances of the proposed methods, and the actual parameters estimation performance of the proposed methods is verified and improved. This project will provide a new idea for the anti-high-power electromagnetic interference of passive radar seeker in E-war complex electromagnetic environment.

近年随着高功率微波技术发展以及高功率微波武器在电子战中的应用，高功率微波源所辐射强电磁干扰导致被动雷达导引头（PRS）空域分辨能力急剧下降。然而强电磁干扰与真实目标的天线极化方式并不完全相同，因此通过感知目标与干扰的极化差异，可提高PRS的波达方向（DOA）与极化参数估计性能。本目项拟借助共形极化可重构天线阵列，首先通过分析共形阵列中强弱入射信号的空间谱统计特性，揭示强信号导致弱信号参数估计性能下降机理；然后研究共形极化可重构天线阵列极化感知优化方法，并研究强弱信号共存时入射信号的参数估计方法，提高弱信号参数估计性能；最后分析共形极化可重构天线及阵列的电磁特性对算法参数估计影响，从提高算法性能角度优化天线及阵列设计，验证并提高算法实际参数估计性能。本项目将为电子战复杂电磁环境中被动雷达导引头抗高功率电磁干扰提供新思路。

电子战下的战场电磁环境极其复杂，高功率微波源所辐射强电磁干扰会影响被动雷达导引头(PRS)对真实目标辐射源的定位。共形天线阵列本身所具有的极化多样性可感知强干扰与真实目标所辐射电磁波的极化差异，因此研究基于共形阵列的弱目标信号参数估计，可提高复杂电磁环境中被动雷达导引头抗强电磁干扰能力。本项目首先研究强信号功率对弱信号参数估计的影响，得到强干扰功率增加会导致弱目标参数估计的克拉美罗界上升，即弱目标参数估计的均方根误差增加，为强干扰会影响弱目标参数估计性能提供了理论依据；发现强干扰与弱目标共存时， DOA估计算法经典性能评价准则存在局限性，通过蒙特卡洛实验验证了，当弱信号信噪比低于5dB时经典评价准则误判率大于50%，提出DOA算法估计性能评价新准则，并证明新评价准则改善了经典评价准则的虚警概率，且具有较好的鲁棒性。其次，为提高复杂电磁环境中强弱信号共存时弱信号参数估计性能，依据入射信号功率改变时噪声空间特征值不变的特性，提出了基于对角加载和基于噪声空间特征值重构的信号参数估计算法，并从理论上证明了本项目所提出算法具有较好的参数估计性能，计算机仿真表明，所提出的算法有效提高了强干扰下弱信号的参数估计性能；提出了一种共形波束可扫描水加载偶极子天线，该天线的工作带宽为14.5%，可实现5种波束状态扫描，其方位面波束覆盖达到360°，天线最高增益为6.7dBi，3dB波束宽度为124°；最后，设计共形偶极子与共形微带天线阵列，研究各阵元辐射方向图不一致性对算法性能的影响，得到各阵元在入射信号方向上的增益离散性越小，算法的参数估计性能越好，加工并测试所设计的天线阵列，搭建实验系统验证了上述分析的正确性，为共形天线阵列与算法的一体化设计提供了新的认知。本项目的研究成果为复杂电磁环境中抗强干扰的弱目标定位提供理论支撑与工程借鉴。