Research On Anti-jamming Signal Processing Of Linear Frequency Modulation Short-range Angle Measurement

The LFM short range detection system has been widely applied in the military field due to its characteristics of high precision,small volume,low cost.The combat environment of modern battlefield is becoming more and more complicated.Therefore,the research of human interference and anti-jamming methods is very important.The paper is about the angle measurement algorithm of sawtooth FM short range detection system,as well as the jamming analysis and anti-jamming technology of sawtooth FM short range detection system.Firstly,the difference-frequency Signal of the sawtooth FM detection system is theoretically analyzed,and the angle measurement algorithm based on all phase fast Fourier transform(apFFT)is studied,and the related simulation experiments are carried out.Secondly,the mechanism of AM jamming and FM jamming is studied,the simulation results show that AM jamming and FM jamming can make the angle measurement performance of the system worse under specific parameters.Anti-jamming algorithms based on Radon-Wigner change(RWT)and fractional Fourier transform(FrFT)are proposed based on the characteristics of jamming signal.The simulation results show that the two algorithms can effectively suppress noise AM jamming,sawtooth AM jamming and partial FM jamming.Finally,the Quartus II software is used to design the FPGA software for the signal processing scheme.The FPGA software design module includes the clock reset signal module,the data storage module,the filter module,the FrFT anti-jamming module and the apFFT module.The modules are verified separately.The results show that all modules can be used normally.The modules are combined to carry out the overall simulation test.The simulation results show that the angle precision of the sawtooth FM detection signal processing system reach 0.48 degree and meet the requirement of the target.