Synthetic Aperture Radar Signal Model And Imaging Algorithm Research

The Sythetic Aperture Lidar (SAL) is the special Sythetic Aperture Ladar with laser carrier wave. The theory of SAL is similar to SAR. For the high frequence and the excellent coherent characteristic of the laser, SAL has the higher resolution, finer anti-jamming performance and higher security in comprison with SAR. The Doppler frequence will be larger for the motion target of the same speed. So that, the larger speed bound targets can be detected. Moreover, the size of antenna and system can be smaller. For these characteristics, it is receiving considerable attention recently.Focusing on the signal processing theories and technique of Synthetic Aperture Lidar, the main work of this thesis is shown as follows:1. The fundamental of SAL is analyzed. And the main structures of SAL system are presented. Then, the function and configuration of these structures are analyzed as well. Furthermore, the key techniques for system realization are introduced.2. The signal models of linear wavelength modulation and linear frequency modulation are analyzed. Then the signal model of linear frequency modulation interrupted continuous wave of stripmap SAL is presented. The echo signal model after heterodyne detecting is given. The resolutions on range and cross-range are analyzed respectively.3. The motion phase error is analyzed. In specific, the deffrent influences of motion phase error on the imaging between SAR and SAL are researched. And the simulation for two modes on the same motion error is given.4. The backprojection (BP) algorithm for stripmap SAL imaging is presented. The main parameters are analyzed as well. Moreover, simulations of deffrent targets are given. The results of simulations verified the performance of the algorithm.5. Focusing on the large calculation shortcoming of backprojection algorithm, a noval fast backprojection (FBP) algorithm for stripmap SAL is presented. This fast algorithm gets improvements from the decreasing of backprojection aperture length and simplification of delay calculation. And the simulation results verified that this algorithm gains the advantage of high precision of the traditional backprojection algorithm and also decreases the calculation.6. BP algorithm and FBP algorithm for stripmap bistatic translationally invariant SAR imaging are presented. Simulation results verify the advantages and specialties of this fast algorithm. The imaging results using FBP for practice flying experiment is also verify the FBP's validity in real system application.