Research On Imaging And Detection Method Of Moving Target In SAR

In recent years,Synthetic Aperture Radar Ground Moving Target Indication technology(SAR-GMTI)has become a hotspot in the field of SAR.Under the background of modern warfare,there are many moving targets in the ground battlefield.Advanced GMTI system can assist in investigating the battlefield situation,obtaining real-time information of the enemy,and monitoring the changes of the enemy's deployment,etc.SAR-GMTI is playing an important role in modern military field.Based on the multi-channel airborne SAR system,this paper deeply studies SAR imaging theory,SAR moving target maging algorithm,clutter suppression and moving target detection technology,and puts forward some new ideas and schemes.The effectiveness of the proposed algorithm and scheme in multichannel SAR ground moving target imaging and detection is proved by simulation and measured data processing.The research contents of this paper are summarized as follows.1.Based on the study of SAR imaging principle and basic algorithm,the multichannel SAR echo model is established aiming at moving targets,and the influence of the change of Doppler parameters caused by target motion on SAR image is analyzed.Range-Doppler algorithm is used to simulate the SAR imaging process of stationary targets and moving targets.2.Aiming at the phenomena of range cell migration,azimuth defocusing and shifting in moving target SAR images caused by parameter mismatch,a high-precision imaging algorithm of moving target based on range-azimuth two-dimensional matching is proposed.Firstly,the range matching method based on Keystone transform is introduced,then the azimuth matching method is introduced and the defocusing caused by the maximum mismatch error is quantitatively analyzed.Finally,the simulation results prove that the moving target imaging algorithm can effectively match the moving target with different motion parameters and improve its focusing degree.This method has the advantages of supporting simultaneous processing of multiple non-cooperative targets,wide matching speed range and adjustability.3.The principle and implementation of Space-Time Adaptive Processing(STAP)algorithm are deeply studied.Emphasis is laid on the further exploration of the post-Doppler STAP algorithm and its application in clutter suppression in multichannel SAR moving target detection.More concretely,a scheme of multichannel SAR moving target detection based on post-Doppler STAP and two-dimensional matching imaging is proposed,which combines the range-azimuth two-dimensional matching imaging method with it.The measured data processing proves that the moving target detection scheme has a good performance of moving target detection.Moreover,this moving target detection scheme is universal to SAR platform parameters,ground moving target velocity and scene clutter characteristics.