Research On Signal Processing Technology Of Pseudo-code Phase Modulation Short-range Detection Radar

In modern battlefield,the confrontation between jamming and anti-jamming is becoming increasingly fierce,which puts forward higher requirements for the anti-jamming performance of short-range detection system in the complex electromagnetic environment.Pseudo-random code short-range radar has low probability of interception and high anti-jamming performance,which has important application value.In this thesis the key problems of sidelobe,Doppler frequency sensitivity and anti-FM jamming are studied.The main work includes:1)Aiming at the problem of rang sidelobe of pseudo-random code short-range radar,the design of mismatched filter is transformed into a second-order cone programming(SOCP)problem by using the theory of SOCP.The mismatch filter is designed with the maximum gain processing loss as a constraint.Simulation results show that this method has a significant improvement on the performance of PSL.2)Aiming at the Doppler frequency sensitivity of pseudo-random code short-range radar,the Doppler frequency compensation algorithm based on MTD is analyzed.In order to improve the accuracy and range of compensation,the apFFT transform is used to detect and compensate the Doppler frequency,which effectively corrects the Doppler mismatch problem.3)Aiming at the problem of pseudo-random code short-range radar countermeasure against FM jamming,the influence of FM jamming on radar is analyzed based on the establishment of mathematical model of typical FM jamming.According to the difference between LFM and SFM jamming and the target echo signal in the time-frequency plane,the SMethod time-frequency analysis and Hough transform are used to eliminate the jamming by estimating the instantaneous phase of the jamming and constructing the adaptive canceller.For the noise FM jamming,the envelope filtering algorithm is used to estimate the characteristic parameters of jamming,to reconstruct the jamming and to cancel with the echo signal,which effectively improves the signal-to-interference ratio.4)A signal processing board based on FPGA platform is developed and debugged.A hardware-in-the-loop simulation(HILS)system is designed to simulate the radar IF echo signal under the action of noise and FM jamming.The algorithms proposed in this thesis are verified by HILS experiments.The experimental results demonstrate the effectiveness of each algorithm.