欺骗环境下GNSS信号估计与定位修正技术  

GNSS signal estimation and position correction algorithm under spoofing attacks

作　　者：许睿[1] 岳帅 唐瑞琪 曾庆化[1] 刘建业[1] XU Rui;YUE Shuai;TANG Ruiqi;ZENG Qinghua;LIU Jianye(College of Automation Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China)

机构地区：[1]南京航空航天大学自动化学院,南京211106

出　　处：《航空学报》2020年第10期298-308,共11页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(61603181,61533008);中央高校基本科研业务费专项资金(NT2018008)。

摘　　要：欺骗信号以其极强的隐蔽性使卫星导航接收机难以察觉并迅速定位到错误位置,严重影响了卫星导航的安全性。现有抗欺骗技术需要其他导航系统辅助来修正受欺骗影响的定位解算,针对该问题,本文提出了一种GNSS欺骗信号参数估计与辨识方法,能够在欺骗干扰环境下估计并辨识出真实信号所对应的伪距,进而解算出接收机真实位置。该方法通过研究欺骗干扰下接收机相关值模型,在信号跟踪阶段建立真实与欺骗双信号状态模型与基于九路相关器输出的观测模型,利用扩展卡尔曼滤波(EKF)估计真实信号与欺骗信号的伪码延时与信号相关幅值,进而获得真实与欺骗伪距,在定位解算阶段利用改进观测量残差检测方法辨识出真实与欺骗伪距,最终使用真实伪距定位获得真实位置。仿真结果表明对相对码延时介于0.3~0.9chip之间且欺骗/真实信号幅度比介于1~5之间的隐蔽欺骗攻击,所提方法的码延时估计误差约0.1chip,可有效估计真实信号与欺骗信号参数,辨识出真实伪距,并使被欺骗的定位结果重新回到真实位置结果,改善GNSS接收机抗欺骗能力,提高卫星导航安全性。Spoofing signals,with high elusiveness,are hardly detected by Global Navigation Satellite System(GNSS)receivers,therefore misleading positioning solutions of target receivers and seriously degrading the safety and reliability of GNSS.Current anti-spoofing methods correct the deceived positioning solutions depending heavily on other navigation systems/sensors.To reduce the reliance,this study proposes a new spoofing signal parameter estimation and identification method which estimates time delays and pseudoranges of both authentic and spoofing signals,thereby distinguishing authentic and spoofing ones and computing receiver positions using selected authentic pseudoranges.In this method,the receiver correlation value model with spoofing interference is deeply studied and used in the Extended Kalman Filter(EKF)-based signal tracking loop to estimate the code delays and the signal correlation amplitudes.In the positioning module,pseudorange residuals are employed to detect real and spoofing pseudoranges,and the authentic pseudorange positioning is used to obtain the true position.Simulation results show that the estimation accuracy of the proposed method is 0.1 chip under spoofing attacks with a 0.3-0.9 chip relative delay and a 1-5 spoofing-authentic-signal amplitude ratio.Generally,with the aid of authentic and deceptive signal parameter estimation loops,the proposed method can effectively identify the spoofing signals of each channel,and return the true positioning solution,thus improving the anti-spoofing ability of GNSS receivers.

关 键 词：GNSS 抗欺骗技术 跟踪环路 卡尔曼滤波 欺骗检测 

分 类 号：V249.3[航空宇航科学与技术—飞行器设计]