Linear Three-dimensional Sar Imaging Algorithm Research And Simulation

Linear array three dimensional (3D) synthetic aperture radar (SAR) is a new SAR system research field, which has the ability to map a directly over?own scene into a high resolution 3-D image by looking perpendicularly downwards, so this system can overcome shading effects better than traditional 2D SAR imaging system. Linear array 3D SAR system uses a linear array antenna mounted in traverse direction, realizes cross-track compression by beaming operation, along-track compression by synthetic aperture principle and range compression by pulse compression technique.This dissertation analyzes the theories of the linear array 3D SAR imaging,introduces the imaging algorithm and several model of this system, finally super-resolution method used in 3D SAR imaging is introduced. The main contributions of this dissertation are as follows:(1) The 3D imaging theories of the downward-looking linear array SAR are introduced. The 3D linear array SAR model are researched , the 3D spatial ambiguity function (AF) and spatial resolutions are analyzed.(2)Research the model of linear array 3D SAR system: downward-looking model, side-looking model, forward-looking model. Analyses the advantages and disadvantages of the model and the algorithm suitable for this mode.(3) Research the imaging algorithm of linear array 3D SAR system, including back projection (BP) algorithm, range Doppler (RD) algorithm, The main steps of these methods are presented. The simulation results validated the feasibility of these 3D imaging methods.(4) 3D CS algorithm is proposed. The traditional CS algorithm combining with beam -forming principle, so as to realize 3D imaging. The CS factor derivation and algorithm procedures are presented. Analyzing the advantages and disadvantages of these algorithm form imaging effect and computational costs .(5) Research the Super-resolution method used in 3D SAR imaging , including MUSIC method and ESPRIT method, The main steps of Super-resolution method used in 3D SAR imaging are presented.