Research On Adaptive Anti-jamming Technology Of Beidou Four-array Antenna

The global satellite navigation system are widely used in scientific research,agriculture,military and other fields with the characteristics of precise timing,high positioning accuracy and strong real-time performance.However,due to the long distance between the satellite and the Earth's surface,the signal transmission power is weak.At the same time,with intentional or unintentional interference increasing gradually,the navigation signals received by the user segment are of poor quality,resulting in imprecise positioning.In order to solvethis problem,a complete anti-jamming scheme of satellite signal user segment was bulit to find an efficient,nlow-cost and stable implementation method and design an extremelly important anti-jamming products which can barrage jamming,capture the navigation information and get the normal precise position even under the harsh electromagnetic interference environment.Based on the Beidou satellite receiving hardware as the development platform and adaptive anti-jamming technology as research object,this paper analyzed and studied the technology of array antenna,interference suppression algorithm and channel mismatch correction in reliance on a company project.At first,this paper described the research status of anti-jamming technology and analyzed the development trend of anti-jamming technology.Then the development course,system composition,working principle,anti-jamming measures,and interference type and implementation mode of the Beidou navigation system were studied.Finally,the types and basic structure of the adaptive filter were analyzed.The convergence criterion of various adaptive algorithms was deduced and compared comprehensively.And the influence of the adaptive antenna principle,the antenna array model and structure on the interference performance was compared.According to the signal characteristics of the Beidou navigation information and the experience guidance given by the relevant project people,the power inversion(PI)algorithm could suppress interference signal based on the minimum variance criterion of multi-linear constraints.However,it could be found that the traditional PI algorithm had obvious effect on the strong interference signal,but faint influence on the weak interference signal when the principle of PI was analyzed and the algorithm formula was iteratively derived.In this paper,a matrix decomposition method was proposed to extract the interference sub-matrix and the noise sub-matrix method.The matrix was judged and processed,and the PI algorithm could be used to eliminate the filter in the case of weak interference.At the same time,the framework of the PI algorithm was designed to determine the process of algorithm,and then the algorithm was simulated in the airspace based on the anti-jamming performance of different array models.The anti-jamming antenna front structure was uniform and the matrix structure was optimized.Finally,each module function of the Beidou four array antenna platform structure was described in detail,and then the design and implementation of the anti-jamming algorithm were described.By setting up the test environment,setting the interference source and collecting the Beidou navigation satellite signal as the input signal,and then through the adaptive algorithm of the module,the interference suppression effect were analyzed.Using Matlab and ISE,the correctness of the design was verified.