Research On Echo Simulation And Signal Processing Technology Of High Speed Target

In recent years,a large number of researches on high-speed flying targets have appeared in the field of aerospace.High speed targets have the characteristics of high maneuverability,ultra long range and low observability.When the observation time is long,there will be serious range migration and Doppler migration.As a result,the performance of traditional target detection technology will decline,and even the target can not be detected,which brings great challenges to the field of radar signal processing.For highspeed target detection,the implementation of field experiments requires a lot of manpower and material costs,which is often unrealistic.Echo simulation technology is an important means of radar development.It can simulate the real characteristics and environmental characteristics of targets in the laboratory,which is convenient for subsequent signal processing research.Therefore,it is of great practical significance to carry out the research on echo simulation and signal processing of high-speed targets.Aiming at the application requirements of echo simulation and signal processing of high-speed targets,this thesis designs an echo simulation and signal processing system with FPGA as the processing core.The main research work is as follows:1.The target echo model is constructed,the range migration and Doppler migration characteristics of the target are studied,and the coherent accumulation algorithm of highspeed target is studied and simulated.2.A high-speed target echo simulation system based on FPGA is designed and implemented.The system includes the simulation of signal generation,digital down conversion,target delay,Doppler,RCS fluctuation model,Gaussian white noise and correlated Rayleigh distribution clutter.A hardware generation method of range migration and Doppler migration is proposed.The motion characteristics of the target are simulated by the method of generating control words in real time.This method can realize the simulation of the migration characteristics of the high-speed target with small error.3.Aiming at the range migration problem of target moving at high speed.An echo signal processing system based on FPGA is designed and implemented,including pulse compression,range rearrangement and range migration correction.The design scheme of high-speed target echo signal processing system is analyzed and demonstrated,the implementation structure of the system is optimized,the pulse compression module based on FFT / IFFT and the data cache and range rearrangement module based on DDR3 are designed,and the implementation method of keystone transform is studied.On this basis,the keystone transform module based on CZT-IFFT is designed and implemented,The designed module can complete the range migration correction of high-speed target with high real-time performance.4.Finally,the echo simulation and signal processing system is built based on VC709 hardware platform,and the Doppler migration compensation and coherent intergration processing are completed in the upper computer.The system designed in this thesis is verified and tested.The test results show that the system can better realize the functions of echo simulation and signal processing of high-speed targets,which meets the expected design requirements.