合成孔径虚拟阵列卫星导航抗干扰技术研究

The background of this project is the interference suppression technology based on synthetic aperture for global navigation satellite system in complex electromagnetic environment. This project conducts the research on interference suppression technology for satellite navigation based on virtual array with synthetic aperture. Emphasis is synthetic aperture navigation interference suppression method based on stationary signal, interference parameter estimation and interference suppression method combined synthetic aperture, and virtual array optimization method for synthetic aperture beamforming. By fully exploiting the advantages of synthetic aperture technology in interference suppression processing of satellite navigation, the degree of freedom (DOF) in anti-interference processing is promoted, new concepts of anti-interference processing are explored, new principles are mastered, and effective new processing criteria, new methods and new algorithms are proposed. The key scientific issues to be solved include the freedom of anti-interference limited by the number of antenna elements, the problem of robust anti-jamming treatment under under-determined DOF, synthetic aperture beamforming affected by velocity and array number. Innovative research achievements have been achieved in such aspects as extending anti-jamming DOF technology based on virtual array technology, robust anti-jamming processing technology combining parameter estimation under the condition of under-determined DOF, and multi-objective optimization algorithm based on virtual array optimal beamforming method. The anti-jamming performance of the receiver will be improved for the future global satellite navigation system, so that the new navigation system with high anti-jamming ability in the future has the key technical support.

本项目拟以复杂电磁环境下全球卫星导航系统合成孔径抗干扰处理为背景，开展合成孔径虚拟阵列卫星导航抗干扰技术研究，重点开展基于平稳信号的合成孔径导航抗干扰技术、联合合成孔径干扰参数估计的抗干扰技术、合成孔径波束形成的虚拟阵列优化方法研究，充分利用合成孔径技术在卫星导航抗干扰处理中的优势，提升抗干扰处理自由度，探索抗干扰处理新概念，掌握新原理，提出有效的卫星导航抗干扰处理新准则、新方法、新算法。拟解决抗干扰自由度受限于天线阵元数、抗干扰自由度欠定条件下稳健抗干扰处理、合成孔径波束形成受速度与阵元数影响等关键科学问题，力求在基于虚拟阵列技术有效扩展抗干扰自由度技术、自由度欠定条件下结合参数估计稳健抗干扰处理技术和基于多目标优化算法的虚拟阵列最优波束形成方法等方面取得创新性研究成果，提升未来全球卫星导航系统接收机抗压制式干扰性能，使我国未来具备强抗干扰能力的新体制导航系统具备关键技术支撑。

随着全球卫星导航系统在国家国防和国民生产生活中发挥的作用愈发广泛，其也面临愈发严重的电磁干扰威胁，导航接收机对干扰抑制的需求日益旺盛。传统导航接收机需采用多天线阵列实现抗干扰处理，成本高昂，设备结构复杂，对硬件要求高。本项目结合合成孔径技术模拟物理多阵元实现抗干扰功能，主要研究内容、结果数据及科学意义分为以下三个方面：.针对抗干扰自由度受限于阵元数目的局限性，本项目建立了卫星导航合成孔径阵列模型，搜星结果显示在三干扰环境下，物理实孔径阵列对卫星信号的接收信噪比约为30dB，合成孔径虚拟阵列卫星的接收信噪比约为27dB，二者抗干扰性能接近；同时结合抗干扰最优加权准则，对接收信号进行空频自适应滤波处理，实验结果表明在干扰处的零陷深度低于-96dB，可有效抑制干信比为60dB的三干扰，结合虚拟阵列扩展自由的优势，实现了多宽带压制式干扰的有效抑制。.针对抗干扰自由度欠定条件下的稳健抗干扰处理问题，本项目采用多重信号分类（MUSIC）算法获取干扰先验信息，实验结果表明MUSIC算法可以精确估计入射信号个数及入射信号方向，实现了多干扰信号的高精度、高分辨力参数估计；给出了合成孔径协方差矩阵展宽算法，实验结果有效扩展了干扰的零陷宽度，实现了干扰的有效抑制；给出了基于FFT的波束形成算法，并推广至二维，实验结果显示二维条件下方向图主波束可以准确指向入射信号方向，实现更高精度的参数估计以及干扰抑制。.针对抗干扰波束形成的多目标优化问题，本项目给出了阵元数目、阵元运动速度等主要参数对波束形成的影响分析，并提出了INSGA-II/SC算法同时优化载体的运动速度和虚拟阵元数，将优化结果反馈到卫星导航合成孔径虚拟阵列的处理模型中。实验结果表明，采用所提算法优化的旁瓣电平能够达到-24.12dB，并且能够保证零陷深度在-60dB以下。实现了干扰有效抑制、信号损失最小和计算量最低的同步优化。