Research On SAR Complex Moving Target Imaging Technology

Synthetic Aperture Radar(SAR)has the advantages of all-weather,all-day and long-distance radar,which can detect,identify and imitate terrestrial vehicles and tanks,and play an important role in military strategy.In recent years,synthetic aperture radar imaging of moving targets has been a hot topic.When the traditional SAR imaging method is used for the imaging of moving targets,because the Doppler parameters vary with time,the moving target image is defocused,and there is a position offset.Therefore,in order to solve the problem of complex moving targets,a new algorithm of SAR based on the phase retrieval is proposed.The main contents are as follows:Firstly,the basic principle of SAR imaging and RD imaging algorithm are introduced.The effect of moving target imaging model and velocity and acceleration on its imaging is studied and the simulation is carried out.Secondly,the basic principle of phase retrieval is analyzed,the oversampling smoothing algorithm is studied,and the phase retrieval theory is applied to SAR imaging.In order to study the SAR imaging performance based on the phase retrieval algorithm,the influence of the selection of the support domain,the noisy parameters,the signal bandwidth and the synthetic aperture length on the performance of the phase retrieval algorithm are studied respectively.The contents of the above research are analyzed and verified by experiments.Finally,based on the analysis of the two-dimensional frequency domain of SAR moving target,a method of re-focusing of SAR complex moving target based on phase retrieval theory is proposed.Firstly,the Keystone transform is used to eliminate the distance of the moving target,and then the phase of the moving target is focused by the phase retrieval algorithm.The algorithm proposed in this paper realizes the high resolution imaging of complex moving targets,and verifies the effectiveness of the algorithm by experimental simulation.