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| A Novel Autofocus Method Based on Short-time Fourier Transform for Airborne SAR |
| Liu Zhong-sheng*①② Li Yin-wei①② Wei Li-deng① Xiang Mao-sheng① |
①(Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China)
②(University of Chinese Academy of Sciences, Beijing 100049, China) |
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Abstract The Short-Time Fourier Transform (STFT) is an important method widely used in the study of the nonstationary signals. After discussing the filtering and the estimation of chirp rate for Linear Frequency Modulation (LFM) signal by using the STFT, this paper proposes a novel autofocus method based on the STFT. The proposed autofocus method firstly utilizes the STFT to estimate and compensate the Quadratic Phase Error (QPE), which is the main part of phase error influencing the quality of the SAR image. And when estimating the residual phase error, the STFT filtering is used for filtering the noise and interference of the time-variant signals to raise the Signal-to-Clutter Ratio (SCR). The experiment results using both simulated data and real data demonstrate the validation of the proposed autofocus method.
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Received: 23 December 2013
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Corresponding Authors:
Liu Zhong-sheng
E-mail: zsliu@mail.ie.ac.cn
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2014, Vol. 36 
