Research On Key Technologies Of Linear Frequency Modulation And Pseudo-code Phase Modulation Close-range Composite Detectio

In order to cope with the increasingly complex electronic environment of the battlefield and improve the range,velocity measurement and anti-jamming performance of the detection system,compound detection is a feasible method.This thesis takes linear frequency modulation and pseudo-code phase modulation composite detection technology as the object,and studies the detection performance,ranging and speed measurement algorithm and anti-jamming performance of the composite system.The details are as follows:(1)Based on the working principle of composite system,the mathematical model of the composite signal detection is established,the time-frequency domain characteristics are simulated and analyzed,the detection performance of composite system is analyzed according to the fuzzy function theory,and the fuzzy graph and related functions are simulated.The results show that the composite system has better ranging performance and clutter suppression.(2)Based on the characteristics of the intermediate frequency signal of the composite system,the correlation method is used to extract the distance information.In order to eliminate the distance Doppler coupling phenomenon and improve the ranging accuracy,the CZT spectrum refinement method is used to measure the frequency,and the time domain undersampling method is used to extract the speed.The simulation results show The composite system has higher ranging measurement accuracy than the single system under the same parameters.(3)Research the Doppler sensitivity,anti-noise and anti-interference performance of the composite signal,use the interference reconstruction cancellation method to suppress the noise FM interference,calculate the system gain,and combine the simulation results to show that the composite signal has better anti-noise and anti-interference Reconstruction method can further improve the anti-interference of the signal.(4)Design the signal processing hardware circuit of the composite system,and complete the logic simulation and verification of the modulation signal and the speed measurement and ranging algorithm based on the verilog language.The intermediate frequency and noise interference signal are simulated through the hardware-in-the-loop simulation experiment.Finally,the hardware and the system are verified by the system cascade experiment.The effectiveness of the algorithm.