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Prior to the next depending on array 3D synthetic aperture radar (SAR) system as an extension of the linear array 3D SAR not only inherits the advantages of the linear array of three-dimensional SAR, break through the traditional SAR can not be forward-looking in the forward-looking imaging and conventional two-dimensional radar can not provide three-dimensional target information constraints, for visual landing of aircraft guidance and navigation, low visibility and target search applications provide a new way, the research focus of the current radar imaging applications. Based on the downward-looking array of 3D SAR system characteristics, mainly for the array of optimization and imaging algorithms, the main work is as follows: 1, first expounded echo model of the downward-looking array of 3D SAR system, and the system distance history, the imaging system is derived based on this three-dimensional resolution equation reveals the space-variant characteristic cut heading resolution, while analyzing the carrier wavelength, platforms, flying height, length of the array, and other system parameters of the cut heading resolution further improve the basic theory of the system. 2, three array optimization method. The bistatic antenna array, there is power series polynomial method, the method uses smaller number of array elements can be obtained with the full array equivalent array characteristics, greatly reducing the required number of array elements. For the first serve multi-antenna array received and spontaneous self-closing, the analysis based on simulated annealing (SA) optimization method and a sparse array of synthetic aperture method, based on non-uniform sparse array SA optimization method using fewer array elements quantity to obtain the same length of the aperture and the full array, and to overcome a uniform sparse array of grating lobe problem, but sidelobe higher. The sparse array aperture synthesis method, the method using the PCA principle the same as the full-array antenna, so that the number and distribution of the phase center after the consolidated, thereby eliminating the problem of non-uniform sparse array sidelobe higher; using the SA-based optimization method. comprehensive array optimization, real array element needs the least. 3, for the lower front view array SAR system, along the heading and distance to the coupling exists, the geometric distortion problem, proposed a suitable lower front of the RD, depending on the array dimensional SAR imaging algorithm. The algorithm in the traditional three-dimensional RD algorithm based on an increase of the secondary range compression, optimized for distance the migration correction factor and compression along the course matching function, geometric correction part to solve the coupled problem of geometric distortion, the algorithm imaging simulation experiments to verify its effectiveness; former under as the array of three-dimensional SAR system, 3D BP algorithm analysis and simulation, relative to the RD algorithm, BP algorithm has a large amount of computation, However, the focusing effect of the imaging results better.
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