Base On FPGA High-Speed Motion Platform For SAR Imaging Real-Time Processing Technology

Synthetic Aperture Radar(SAR)is an important branch of microwave radar technology,which has important application value in high-precision surface imaging,target detection,disaster detection,ice layer and pollution mapping,etc.The real-time performance and miniaturization of its imaging processing system have become current research hotspots.With the development of semiconductor technology,traditional DSP implementation of SAR imaging has limited its application on missile platforms due to its slow speed,large volume,and high power consumption.The main work of this article is to implement complex SAR imaging algorithms on the FPGA platform and construct a real-time imaging system on the missile platform.The main work of this thesis includes:(1)In response to the characteristics of large squint angle and large motion error of missile borne SAR platforms,this thesis conducts research on data containing motion errors.Based on the analysis and comparison of several types of imaging algorithms,improvements have been made to the SPECAN algorithm.The improved algorithm can obtain accurate azimuth matching filtering functions by accurately estimating Doppler center frequency,Doppler modulation frequency,and higher-order phase,thereby improving imaging quality.By constructing a multi-point target simulation model in Matlab,the effectiveness of the improved algorithm in the presence of large motion errors on the platform was verified.The results showed that the improved algorithm can achieve clear imaging.Finally,the improved algorithm was applied to measured data,demonstrating its practical application value and effectively compensating for the impact of motion errors on phase.(2)Completed the design of the entire algorithm on the hardware system,and implemented the processing flow of the algorithm backbone using two XC7VX690 T FPGA chips.The processing of FPGA mainly includes digital down conversion of echo data,range pulse compression,range walk correction,azimuth compression,and slope conversion.(3)The cascade debugging of the entire FPGA system was completed using the simulated echo data generated by the radar simulator,and the system processing results were compared with Matlab processing results to verify the correctness of the system design.This algorithm can be well applied to most missile based platforms,meeting certain imaging accuracy while meeting corresponding real-time processing requirements.