Based On The Pca Principle Of Three-dimensional Linear Array Sar Imaging Principle And Algorithm Research

Airborne virtual linear array three dimensional (3D) synthetic aperture radar (SAR) is a new SAR system, compared with traditional 2D SAR imaging systerm, this systerm can overcome shading effects, allows to image urban areas, street canyons, moutain areas, deep valleys and other areas with strong height changes. Airborne Linear array 3D SAR systerm uses a linear array antenna mounted in traverse direction(the direction vertical to the height and along-track plane), working at down-looking model, 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 SAR imageing principle,introduces the several model of this systerm, prsents the results of emulation and error analysis ,The main contributions of this dissertation are as follows:(1) The geometrical model and echo modelof the airborne linear array 3DSAR imaging systerm are build, the range histroy is analyzed, spatial ambiguity function (AF) and resolving power of the three direction are derived.(2) The several model of the airborne linear array 3DSAR imaging systerm are researched,include:setted transmitting and all receiving, random transmitting and all receiving, multiple transmitting and all multiple receiving, single transmitting and single receiving. The linear array design is discusseed, such as the state(active or not)of the antenna element, PRF and resolving power of the several models, at last the several models are compared and a conclusion that the multiple transmitting and all multiple receiving model is suitable for practical application is obtained, and this model based on phase center approximation (PCA) theroy.(3) The 3D range Doppler (RD) algorithm of airborne linear array 3DSAR imaging systerm worked in the model with the transmitting elements at the tips and the receiving elements in between are researched, the simulation results are presented to validate the feasibility of this model to rebuild 3-D scene, 3D back projection (BP) algorithm of this systerm are researched,the simulation results is presrnted, and the two .algorithms are compared from imaging quality and calculation cost. (4) The motion errors for the airborne linear array 3DSAR imaging systerm worked in the model with the transmitting elements at the tips and the receiving elements in between are analyzed, include velocity error, acceleration error,the influence of the errors to the point spread function (PSF) is validated by simulation results, a model for linear array vibrating error is bulid, the influence to PSF of this error is analysed.