Design And Simulation Of Digital Signal Processing System Of Laser Seeker Based On FPGA

Precision-guided weapons have become one of the indispensable means of attack in modern high-tech local wars,among them,laser precision-guided weapons are favored and become weapon equipment for various countries to compete for development.The semi-active laser precision guidance technology is currently the most widely used technology in the field of laser guidance in China,and it is also one of the key directions of China's current weapons research and development.According to the working principle of target recognition and tracking of semiactive laser seeker,a digital signal processing system of laser seeker based on FPGA is designed in this paper.The system adopts high-speed digital acquisition technology to effectively retain the complete information of the pulse signal,which can realize the enhancement and detection of weak pulse signal,the recognition of pulse code type,the control of time wave gate,the extraction of pulse signal,the anti-jamming of high repetition frequency signal and the tracking and positioning of the target.This paper first introduces the development background of laser guided weapons,and shows the necessity of studying the digital signal processing system of laser seeker.Then the principle of laser guidance is introduced,and the signal processing system of laser seeker is composed of four-quadrant detector,logarithmic amplifier,high-speed digital acquisition,FPGA and DSP.Based on this,the overall design idea of the laser guidance digital signal processing system is proposed.Secondly,each module designed in the signal processing system of laser seeker is described in detail,including the signal enhancement module,decoding module,gate control module,pulse extraction module implemented in FPGA and the algorithm module of anti high repetition frequency interference and positioning algorithm implemented in DSP.In the signal enhancement module,a signal enhancement scheme based on synchronous accumulation method and matched filter is proposed,and verified by simulation on MATLAB.In the decoding module,the characteristics of different code types are introduced,and the decoding process is described in detail.In the wave gate control module,the wave gate control scheme of fixed wave gate and real-time wave gate is proposed,and it is described and verified.In the pulse extraction module,the method of extracting the whole pulse information is adopted.In the positioning algorithm module,this paper does not make in-depth study,and uses the most classic addition and subtraction algorithm to calculate the azimuth deviation.Next,the paper introduces the relevant knowledge of high repetition frequency interference and the current commonly used anti high repetition frequency interference methods,and analyzes their shortcomings.Then,based on the wavelet analysis algorithm,an improved algorithm of anti high repetition frequency interference based on the correlation of pulse signal amplitude,position and width is proposed,and the simulation of the proposed anti-high repetition frequency interference algorithm is fully simulated on MATLAB.Finally,based on Vivado software,the function modules based on FPGA design in the signal processing system were simulated and verified,and the simulation results are analyzed and explained,indicating that the designed digital signal processing scheme can meet the requirements of the system.