基于信号方向和伪距延迟特性的联合空时GNSS抗欺骗式干扰

Manipulating disguised GNSS signals, spoofing attacks are able to get access to receivers. The spoofing signals offer false position or time information of satellites in order to misguide the receivers in confrontational circumstances. Thus spoofing attack will cause more damage than conventional jamming attacks. For military users, who take advantage of cryptographicpseudo-randomcode, the ordinary spoofing attacks adopting unencrypted civil signals can be detected, which is the core of most anti-spoofing theories in current days. However, if spoofing attacks elaborate to broadcast perfect replicas of genuine military signals, traditional anti-spoofing mechanisms, which focus on spectrum characteristics detection, military authenticated encryption, or signal power, are unable to detect attacks, let alone suppress them. Therefore, it is very meaningful to investigate a new theory to identify and suppress the spoofing attack when the convergent and distributed spoofing attacks take places in the same time.. Combining the spatial characteristics of spoofing signals and the time characteristics of pseudo-range delay, this project presents systematical research on anti-spoofing techniques. (1) To detect spatial convergent spoofing attacks, we present spatial eigenvector based detection theory, and suppress them by utilizing antenna arrays, whose null is set to aim at the direction of spoofing signals. (2) According to the common characteristics of pseudo-range delay in convergent and distributed attacks, we proposed an anti-spoofing theory with optimum matching of particle filter measurement vectors relevance and robust solution. (3) Furthermore, to make the detection and suppression mechanisms more reliable, we also put forward joint estimation with attitude and direction of arrival..

欺骗式干扰伪装GNSS信号提供错误的信息，因其在对抗中具有误导接收机的能力，与传统压制式电磁干扰相比，欺骗式干扰的危害更大。在针对军用信号的分布式欺骗干扰模式下，传统的抗欺骗式干扰理论，如利用频谱特性、军用加密验证或信号能量检测等方法已无法抑制干扰甚至无法检测出干扰的存在。因此，研究在聚合式干扰和分布式干扰复合环境中，能够有效甄别并消除干扰的新理论具有重要的现实意义。. 本项目联合欺骗式干扰信号的空间特性和伪距延迟的时间特性，对检测与抑制欺骗式干扰理论进行研究。(1) 对空间聚合式的欺骗式干扰，提出空间特征向量检测理论，然后利用天线阵列在空间最大能量到达方向形成零陷从而抑制干扰；(2) 基于聚合式和分布式的欺骗式干扰共有的伪距时延特性，提出利用粒子滤波观测矢量相关性最优匹配的干扰检测和基于稳健解算的干扰抑制理论；(3) 最后提出姿态-到达角联合估计理论，提高检测与抑制的可靠性。

背景：.随着电子信息技术的蓬勃发展，全球导航卫星系统（Global Navigation Satellite System， GNSS）在基于位置服务中的核心作用愈发显著。然而，在GNSS技术被各行业广泛应用的同时，其潜在的风险也引起了广泛的关注。GNSS信号很容易受到频带内的压制式干扰与欺骗式干扰的攻击。欺骗式干扰旨在利用转发或者伪造的错误导航信息去误导GNSS接收机。欺骗式干扰信号与真实信号具有很高的相似性，它们与空间中的卫星信号混在一起进入接收机难以区分。干扰方可以在接收机毫无察觉的情况下破坏甚至控制定位定时结果，因而欺骗式干扰比压制式干扰威胁更大。极端情况下干扰源可以借助多个精心设计的干扰信号，使被干扰的接收机载体按照欺骗者设计的轨迹到指定的区域，这对于无人驾驶的汽车、飞机或导弹等的威胁非常严重。.主要研究内容：.1).基于信号空间特征的抗聚合式欺骗式干扰.2).基于粒子滤波观测矢量匹配理论的抗欺骗干扰.3).基于姿态-到达角联合估计的抗欺骗干扰.重要结果：.1).为了提高在天线端的检测识别能力，提出了基于RELAX算法的抗欺骗式干扰方法。.2).为了更好地抑制欺骗式干扰，提出了基于子空间投影的GNSS欺骗式干扰消除算法。.3).为了提高GNSS接收机的定位解算精度，提出基于粒子滤波的GNSS抗欺骗式干扰研究。.4).针对现有抗干扰方法的算法和硬件复杂度都较高，设计了一种基于多普勒频移的抗欺骗式干扰方式。.科学意义：.1).提出研究抗欺骗式干扰的新对象。将欺骗式干扰分为聚合式和分布式两类，将其内在的规律性和外在的表现形式进行梳理，形成清晰的学术内涵，使之从直观形象上上升到学术意义。.2).提出研究抗欺骗式干扰的新视角。从欺骗式干扰信号空间特性和时延特性角度入手，站在信号层和信息层两个层面协同观察和分析，将原本单一独立的理论结合起来。.3).提出研究抗欺骗式干扰的新方法。将最优化粒子滤波引入到信息解算中，分析欺骗是干扰的伪距延时特性；利用观测矢量相关性最优匹配和稳健估计实现抗聚合式和分布式欺骗干扰。