Research On GNSS Anti-spoofing Scheme Based On Cubature Kalman Filter

Global Navigation Satellite System could provide positioning and navigation services for people,and it has become an indispensable part of our daily life.At the same time when it is widely used,the spoofing attack is being the potential risk for its safety.This kind of attack could forge fraudulent signals to insensibly mislead the receiver to have wrong time and positions,then the impact thereof is inestimable.The paper proposes an anti-spoofing method based on Cubature Kalman Filtering algorithm and Receiver Autonomous Integrity Monitoring theory,which could not only improve the positioning accuracy,but can also detect the spoofing attack effectively.Firstly,based on the real-time ephemeris parameters received by the NovAtel OEM6 receiver,the positions of GPS and BDS satellites are calculated.Combined with the pseudo-range measured,the C language programs are established to calculate the user's position by using the Least Square and Kalman Filtering algorithm.In order to improve the accuracy,the Cabuture Kalman Filtering algorithm is introduced into the calculation process.The results show that the CKF can provide a higher positioning accuracy than LS and KF algorithm.Subsequently,the spoofing attack mathematical model has been established.Both two kinds of spoofing attack,forwarding spoofing attack and generating spoofing attack,mislead the user by adding extra pseudo ranges which are carried on deception signal.According to the different features of extra pseudo ranges,the spoofing scenario can be further divided into mutational and slowly varying pseudo-range scenes.In each spoofing attack scenario,the positioning errors signify that three algorithms themselves do not have the ability to resist spoofing attack.Finally,an anti-spoofing method combined with CKF and RAIM is proposed.Constructing the pseudo-range residual statistics,then the spoofing detection threshold could be calculated when the false alarm rate is known.If the value exceeds the spoofing detection threshold,it signifies there exists spoofing attack.The spoofing attack recognition is based on the covariance diagonal elements of the residuals vector.To look for the maximum value to discriminate the satellite being spoofed.Through different spoofing attack scenarios simulation,the feasibility of the proposed method has been verified.The Monte Carlo simulation results show that the proposed method base on CKF and RAIM can effectively detect and identify the fraudulent spoofing signals.