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| Study of Autofocus Method for SAR Imagery Created by Fast Factorized Backprojection |
| Li Hao-lin Chen Lu-lu Zhang Lei Xing Meng-dao Bao Zheng |
| National Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, China |
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Abstract The Fourier Transform Pairs (FTP) between the image domain and its corresponding range-compressed phase history domain is critical for autofocus. Different from the frequency-domain algorithms, this requirement of FTP is both complicated and difficult to be met in the time-domain algorithms. For a swift and effective reconstruction and autofocus processing of imagery created by the time-domain algorithm, the necessary improvement and optimization in the Fast Factorized Back-Projection (FFBP) is performed, presenting an Improved FFBP (IFFBP) algorithm further. Through the pseudo-polar coordinate system, the IFFBP is able to pave the way for autofocus application. Also, in view of the practical requirements for data processing, the IFFBP uses a moderate-accuracy Inertial Measurement Unit (IMU) to achieve a coarse compensation，and combines with the Phase Gradient Autofocus (PGA) to make a fine compensation. Finally, the simulation results and the collected data sets verify and validate the proposed approach.
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Received: 05 January 2013
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Corresponding Authors:
Li Hao-lin
E-mail: lihaolin322@163.com
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2014, Vol. 36 
