Research On Anti-jamming Of BeiDou System Receiver Based On Adaptive Spatial Notched Filter

The adaptive spatial notched filter technology has attracted more attention due to its excellent anti-jamming ability,which is widely used in satellite navigation system fields.This thesis focuses on the anti-jamming problems of Bei Dou satellite navigation system receiver based on adaptive spatial notched filter technology.Firstly,an adaptive spatial notched filter anti-jamming scheme based on the power inversion algorithm is proposed for the receiver under compression interference,and the simulation results show that the algorithm can effectively suppress the interference signal.Secondly,the hardware platform of the adaptive spatial notched filter preprocessing system is built,and the synchronization algorithm of baseband signal is simulated.Finally,this thesis gives some Suggestions on the improvement of adaptive spatial notched filter technology.The main research results of this thesis are as follows:1.This thesis studies the anti-interference performance of adaptive spatial notched filter technology.Firstly,the interference tolerance of Bei Dou system receiver is given according to the criterion of receiver interference determination.Secondly,according to the working principle of power inversion algorithm,an optimal weight vector algorithm for array antenna based on SMI method and LMS method is proposed.The advantages and disadvantages of the algorithm are summarized by simulation analysis from three aspects: zero notch pattern,anti-jamming ability and convergence performance.Thirdly,in order to improve the convergence performance of the LMS-based adaptive spatial notched filter algorithm,two power inversion optimization algorithms with variable step size are proposed: the segmented variable step power inversion algorithm adjusts the algorithm iteration step size according to the different processing stages of the signal,adaptive variable step power inversion algorithm automatically adjusts the algorithm iteration step size according to the change of signal power value,simulation results show that the two optimization algorithms can improve the convergence performance of the power inversion algorithm.Finally,this thesis builds an anti-jamming simulation system of receiver spatial notched filter algorithm cascaded beamforming algorithm,analyze the working principle of beamforming algorithm,and give the simulation system structure and anti-interference test results.2.This thesis studies the hardware implementation of receiver adaptive spatial notched filter anti-jamming algorithm,build the anti-jamming pretreatment system of the receiver.this thesis introduce the hardware composition and working principle of the system,analyze the clock design of baseband signal processing,the communication between system hardware and the FPGA design of the key module of algorithm.This thesis briefly introduces the synchronization algorithm principle of baseband signal,proposes an extended integral time acquisition algorithm based on PMF-FFT algorithm,and analyzes the working principle and performance of the tracking algorithm.3.This thesis puts forward some suggestions to improve the adaptive spatial notched antijamming technology,analyze the working principles of space time adaptive filtering technology,adaptive spatial notched filter technique based on cross-division subarrays and inertial navigation assisted receiver anti-jamming technology,give the frequency distribution of Bei Dou anti-jamming system and the hardware structure adjustment of adaptive spatial notched pretreatment system.