Research On Chirp Fuze Jamming And Anti-jamming Technology

LFM fuze has the advantages of high distance resolution,no distance dead zone,and strong anti-interference ability.It has been widely used in various ammunitions.Electronic countermeasures for LFM fuze have also drawn the attention of many researchers.At present,the signal processing of LFM fuze usually adopts the method based on differential frequency ranging and speed measurement or the method based on harmonic comparison distancedetermination to control the detonation.This paper studies the interference and antiinterference technology of LFM fuze based on the above two signal processing methods.Firstly,the paper analyzes the theory of two signal processing methods of LFM fuze,and builds a simulation model of LFM fuze based on MATLAB / Simulink.The simulation results verify the correctness of signal processing algorithms and the simulation model.Secondly,a positional relationship model between the jammer and the fuze trajectory is established.Based on this,the paper analyzes the influence of signal processing and startup output of LFM fuze under deceptive interference and suppressive interference.Then,an interference model is constructed for simulation verification.For LFM fuze based on differential frequency ranging and speed measurement,DRFM-based interval-forward interference,multi-target superimposed interference,and the noise AM interference whose SJR is-10 d B will affect its normal startup output.For LFM fuze based on based on harmonic comparison distance-determination,the effect of deceptive interference methods including DRFM-based interval-forward interference,sinusoidal AM sweep interference,and multitarget superimposed interference is more prominent.Noise AM interference requires higher interference power.Then,based on the mechanism of various interferences,the paper proposes a decisionmaking method based on cross-correlation detection and an anti-interference algorithm based on filtering in fractional order domain.Simulation results show that these two methods can suppress the interference and enhance the anti-interference performance of fuze.Finally,the software and hardware design of suppressing noise AM interference is completed.The signal processing circuit board is fabricated through Schematic and PCB design.The FPGA implementation of the discrete FRFT algorithm is completed based on the Verilog HDL language,including program writing,compilation,and function tests.The Antiinterference experiment is conducted in the laboratory.The results show that this method can effectively improve the startup output probability of LFM fuze within the distance threshold.