The Amplitude And Phase Error Estimation And Compensation Technology Of Wideband FMCW Radar

Signal design and generation is the key technology in the radar field,LFM signal distortion directly affect the resolution of the radar system,and further affects the image quality.It's difficult to maintain substantial absolutely flat and strict linear phase for FMCW SAR under the large bandwidth condition.As we know,the signal amplitude and phase distortion will significantly affect the radar system performance,so it's important to study the amplitude and phase error calibration technology of the frequency modulated continuous wave signal.In this paper,we mainly study the estimation and compensation technology of amplitude and phase error for wideband frequency modulated continuous wave radar system.Taking the specific SAR FMCW system as an example,signal generation,transmission,reception methods and implementation techniques are analyzed,in order to further study the source of amplitude and phase error,as well as the affect and the correction of the amplitude and phase distortion.The main works are as follows:1.This paper describe the system composition and working principle of the frequency modulated continuous wave radar system,then analyze the digital generation of wideband radar signal and the principle of LFM signal pulse compression and mainly compares the difference and similarities between DDWS and DDFS from signal waveform characteristics and error representation.2.Based on the principle of broadBand frequency modulated continuous wave radar system,amplitude and phase distortion introduced by each module in the generation,transmission and reception is analyzed.Then,the signal amplitude and phase error model is established to study the influence on the signal pulse compression under different kinds of amplitude and phase error,and some simulation proved the analysis.Finally,according to the model,two estimation methods of signal amplitude and phase error,the time domain integral extraction method and the frequency domain spectrum comparison method,are analyzed.3.According to the signal amplitude and phase error model of closed loop radar system and the theory of linear systems,the feasibility of digital predistortion compensation for the radar system is studied,and the model with frequency doubling chain system is further analyzed to study how to process it reasonably.Then,by comparing and analyzing two kinds of amplitude and phase error estimation methods,the time-domain integral method is selected to extract the error of the FMCW SAR signal.Meanwhile the digital predistotrion correction scheme is designed;in addition,the simulation and experiment are finished to verify the feasibility and effectiveness of the program.Finally,aiming at the frequency modulated continuous wave signal after the digital predistortion correction,the second stage correction for the phase distortion is completed at the signal receiving end,which is based on the RVP filter.