Research On The Interference Mitigation Algorithm Of Satellite Navigation Receiver

With the rapid development of global satellite navigation system(GNSS),more and more applications in military and national economy rely on GNSS to provide accurate position,navigation,time(PNT)services.However,due to the vulnerability of the satellite navigation system and the development of electronic technology,man-made interferences including jamming and spoofing have gradually become an important threat to the safety of the GNSS.It has great necessilty and urgency to research the interference suppression technologies of satellite navigation receiver.This dissertation focuses on robust anti-jamming methods based on antenna arrays,the GNSS spoofing detection algorithms based on signal characteristics monitoring and interference suppression technology in complex environment.The works are mainly as follows:To solve the problem that the traditional anti-jamming algorithms with arrays lack robustness,two robust anti-jamming algorithms with arrays are proposed.Firstly,a robust spatial adaptive processing anti-jamming algorithm based on coloured diagonal loading is proposed to widen the beam nulling.Secondly,to solve the problem of GPS space-time adaptive processing anti-jamming algorithms suffer from performance degradation in the presence of covariance matrix estimation errors and steering vector mismatch,a robust space-time anti-jamming algorithm based on convex optimization is proposed.The algorithm reconstructs the interference plus noise covariance matrix by Capon spectral estimation method and correctsthe steering vector by convex optimization equations,finally gets the space-time filter weights,and reduces the influence of array errors and steering vector mismatch.To solve the problems that the traditional spoofing detection algorithms based on signal quality monitoring fail to make full use of the correlator outputs and have low detection accuracy,an improved signal quality monitoring technique of spoofing detection algorithm is proposed.The improved signal quality monitoring method utilizes the early,late and prompt of in-phase and quadrature correlator outputs.The detection factor is amplified nonlinearly by the arctangent function.The Texas spoofing test battery(TEXBAT)is used for verification.The experiments show the proposed method improves the spoofing detection accuracy.To solve the problem that the traditional spoofing detection methods with arrays have limited application range and can only detect single source spoofing,a GPS spoofing detection method based on combined power and DOA monitoring is proposed.It uses the compressed sensing DOA algorithm of off-grid sparse Bayesian inference and detectes the spoofing from the rationality of power and DOA.The simulation results show that the proposed method can effectively detect the GPS spoofing in single source and multi-source spoofing scenarios.To solve the problem that the single type anti-jamming algorithms fail in complex electromagnetic interference environment,an interference mitigation algorithm for GPS jamming&spoofing attack and an interference mitigation algorithm for GNSS spoofing&multipath are proposed.(1)In a combined jamming and spoofing attack scenario,the jamming is eliminated by subspace projection,and then,the compressed sensing algorithm is used to detect the spoofing signal.According to the DOA of the authentic and spoofing signals,the receiver uses adaptive multi-beamforming to receive the authentic satellite signal and suppress the spoofing.The simulations show that the proposed method can detect and suppress GPS jamming and spoofing effectively.(2)In the spoofing and multipath coexistence environment,the proposed algorithm uses the PUMA method to calculate the DOAs of the authentic satellite,spoofing and multipath.The authentic DOA is recognized according to the almanac/ephemeris.In the end,the oblique projection adaptive beamforming is used to receive the real satellite signals and mitigate the spoofing and multipath.The simulations show that the proposed method can effectively suppress the GNSS spoofing and multipath.