Study On Interference Detection And Identification Technology Of Beidou Satellite Navigation

Beidou navigation system is confronted with great challenges in terms of continuity,integrity and usability due to the complex electromagnetic environment.Interference monitoring technology can monitor the interference state in real-time,give the interference type,azimuth and its distribution in the space,is the key technology to measure and solve the navigation usability problem.At the same time,this technology can also be combined with anti-jamming technology to enhance the positioning ability of navigation receivers in complex environment.Based on the review of research status of interference monitoring technology at home and abroad,the suppressing interference detection,identification and direction-finding technology of Beidou navigation system are studied.The main contents of the paper are as follows:1.Three kinds of interference detection algorithms are studied,including the mean single threshold energy detection algorithm,absolute double threshold energy detection algorithm and adaptive multi-threshold energy detection algorithm,the performance of each algorithm is verified by Monte Carlo simulation.2.An algorithm based on Rayleigh averaging statistics is proposed to detect the interference frequency point.The algorithm does not need to detect and update the threshold iteration,has the same detection probability as FCME algorithm with a dry-noise ratio above 40dB,is suitable for engineering implementation.3.The Wigner distribution,Wigner-hough Transform and wavelet transform are applied to the suppression interference feature extraction of Beidou navigation system.Seven characteristic factors of suppressing interference are proposed,which are interference presence factor,interference 3dB bandwidth,interference spectrum kurtosis,audio interference coefficient,interference time domain kurtosis,Wigner-Hough kurtosis and wavelet coefficient peak-to-average ratio.Through these characteristic factors,an interference classification recognizer is established by using decision tree theory and obtained a significant recognition effect.4.MVDR beamformer and MUSIC algorithm is applied to estimate the DOA of suppressing interference,and the simulation experiment proves the feasibility of this method.To solve the problem that the accuracy of direction-finding algorithm is influenced by the mutual coupling of antennas,the mutual coupling matrix and the amplitude-phase difference matrix were extracted by HFSS,and their inverse matrix were substituted into the algorithm to correct the results.Computer simulation experiments prove this method is effective.