Research On The Algorithm Of Multichannel SAR-GMTI

The synthetic aperture radar systems for detecting ground moving targets are widely used.For military use,it can realize reconnaissance and early warning of battlefield targets,and then surveillance or attack.For civil use,it can monitor the sea surface and road,which is conducive to environmental protection and traffic information collection.Therefore,it is of great significance to research the SAR moving target detection technology.As the key part of moving target detection,clutter suppression algorithms have problems to be solved.Such as high false alarm rate in non-homogeneous environment with image domain,large quantity of data with data domain.In order to make improvement,this article mainly focuses on multichannel SAR-GMTI algorithms.This article firstly derives the signal model of the multichannel SAR-GMTI,based on which the characteristics of the targets in a SAR image are introduced.It analyzes the main factors that have effect on moving target imaging.Subsequently,the range walk of moving targets at a greater distance than stationary ones is studied,and the two correction methods are simulated,which provides a reference for designing algorithms.This article secondly introduces two types of clutter suppression algorithms.The first one,adaptive clutter suppression in the image domain,is based on the DPCA principle.Two kinds of adaptive clutter suppression methods in image domain are compared through computer simulations.The influence of registration error is analyzed,and an improved method with sample-preselecting is proposed.The simulation verifies the effectiveness of the method,that is,it can improve the suppression.The second type of clutter suppression is in the data domain based on the STAP principle.Starting from array signal processing,adaptive processing is introduced to bidimensional occasion,space and time,by which the principle of STAP is explained.The difference and connection between it and DPCA are elaborated subsequently.Through simulation,common distribution forms of clutter spectrum are enumerated.In order to solve the problem of excessive data throughput,an adaptive weight vector solution based on eigenbeam is proposed.The simulation verifies the effectiveness of this method in both full-dimensional and reduced-dimensional cases.Finally,based on the clutter suppression in the image domain,combined with imaging,preprocessing and relocation,a complete SAR-GMTI processing chain is proposed based on the azimuth dechirp SAR imaging technology,which is verified by the measured data of a three-channel airborne SAR.The detection and relocation results of the cooperative target scene and the non-cooperative target scene are given.Test results and performance analysis prove the feasibility of the entire algorithm.