Research On The Beidou Detection And Suppression Of Spoofing Interference

Due to the openness of civil Beidou satellite signal coding format,navigation message,and the low power of civil Beidou satellite signal to the Beidou ground receiver,it is easy to fabricate the pseudo Beidou signal source,transmitting the pseudo satellite signal and cheating the ground Beidou receiver.Aiming at the problem that Beidou receiver is vulnerable to spoofing interference,the dissertation studies the detection and suppression of spoofing interference in Bei Dou Navigation Satellite System(BDS).Firstly,the dissertation introduces the background,current situation and research significance of GNSS spoofing interference detection and suppression technology.Secondly,the generation mechanism of the navigation satellite signal and the principle of the receiver positioning according to the navigation satellite signal are studied,and the characteristics of autonomous spoofing interference and forwarding spoofing interference are analyzed.Thirdly,two distributed detection methods for Beidou deception interference are proposed.Finally,based on the array antenna,the angle resolution of traditional Relax algorithm is analyzed,and without changing its resolution,the dissertation proposes the A-RELAX algorithm,which can adaptively detect the number of deceptive jamming sources and DOAs,and then suppress the pseudo satellite signal by beam-forming method to suppress Beidou spoofing interference.The main work and innovation of the dissertation are as follows:1.The dissertation proposes two distributed detection methods for spoofing interference.Among them,the method based on the signal-to-noise ratio extracts the signal-to-noise ratio characteristics parsed by the distributed receiver modules,compares the variance of the difference between the signal-to-noise ratio parsed by the two receiver modules with threshold,so as to judge whether the Beidou receiver receives spoofing interference;The method based on the relative distance extracts the positions of the distributed receiver module.According to the location features,the distance between the location of two points is compared with the actual physical distance,so as to determine whether the Beidou receiving module is subject to spoofing interference.Finally,the effectiveness of these two distributed spoofing interference detection methods is verified by experiments.2.Aiming at the problem of DOAs detection of multiple deceptive interference sources,the dissertation makes further research on RELAX algorithm.Firstly,a method is proposed to estimate the relationship between the resolution angle of RELAX algorithm and the number of antenna elements by weakening the weight factor.Secondly,the operation logic of RELAX algorithm is studied.The fact that RELAX is terminated according to the condition of estimating the number ofsignals is changed.And A-RELAX is terminated according to the result of power decision instead.The A-RELAX algorithm proposed in the dissertation can obtain DOAs of all pseudo satellite sources in different environments.Finally,the method of constructing spoofing orthogonal interference subspace can suppress the pseudo Beidou satellite signals without affecting the normal satellite signals.