Research On Video SAR Imaging Algorithm And Software Design

Video SAR has the characteristics of high frame rate,high resolution,low delay,etc.At the same time,with the increasingly mature manufacturing process,video SAR has great research value and potential.Video SAR can continuously observe the target area and continuously image the echo data obtained.However,the radar platform is prone to external interference and vibration,leading to the deviation of antenna phase center,which has a great impact on the image frame rate,resolution and image quality.Therefore,it is necessary to conduct in-depth research on video SAR system,video SAR imaging,motion compensation algorithm and other aspects.This thesis will carry out research based on video SAR motion compensation algorithm,mainly including preliminary motion compensation research based on known motion error and software implementation of motion compensation algorithm.The main work of the thesis includes:1.Firstly,the system frame rate and imaging frame rate of video SAR are analyzed,the frame rate and imaging characteristics in different frequency bands are compared,and the principle of forming high frame rate in terahertz band is analyzed.At the same time,the frequency de-tuning and de-skew processing of video SAR system are analyzed,and the echo signal after frequency de-tuning is derived.The circular SAR imaging model is further established,and the common video SAR imaging algorithm is analyzed to analyze its characteristics in the terahertz band.Finally,the source and classification of motion error are discussed,and two motion compensation methods are discussed,and the flow of self-focusing motion compensation algorithm is deduced in detail.2.Secondly,research on motion compensation based on inertial data is carried out.Circular bunching SAR imaging model is established first,and analyzes the mode of the phase error,error of inertial navigation system are analyzed at the same time,to coordinate transformation of the original data,according to the measuring data envelopment compensation and phase error correction,the antenna with spoil derivative according to the location of the information of the radial motion compensation,will get the phase error integral projection speed information,In this way,the azimuth motion compensation is completed.After the initial compensation,the self-focusing algorithm is used for further compensation.Finally,the simulation and measurement results are given.3.Finally,the software of video SAR imaging motion compensation is designed and implemented.Based on the compensation algorithm in chapter 3 and the original upper computer,the motion compensation software is implemented.Firstly,the INS software is designed to complete the functions of analyzing inertial data,coordinate conversion,projection calculation and so on.The real-time processing research of motion compensation is further carried out,including the modification and implementation of communication transmission,imaging processing,result display and other modules,so as to realize the motion compensation and self-focusing motion compensation algorithm based on inertial data.Finally,the experimental results of circular SAR and strip SAR are given to verify the validity of the compensation algorithm and upper computer software.