一种基于短时傅里叶变换的机载SAR自聚焦算法  

A Novel Autofocus Method Based on Short-time Fourier Transform for Airborne SAR

作　　者：刘忠胜[1,2] 李银伟[1,2] 韦立登[1] 向茂生[1] 

机构地区：[1]中国科学院电子学研究所微波成像技术重点实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《电子与信息学报》2014年第11期2705-2710,共6页Journal of Electronics & Information Technology

基　　金：国家重大专项项目(30-H37D01-9004-13/15);中国科学院装备研制项目(YZ201107)资助课题

摘　　要：短时傅里叶变换(Short-Time Fourier Transform,STFT)是研究非平稳信号最为广泛使用的重要方法。该文在讨论了利用STFT对线性调频信号(LFM)进行滤波以及调频率估计后,提出一种基于STFT的机载SAR自聚焦算法。该算法首先利用STFT对影响SAR图像质量的主要相位误差二次相位误差(QPE)进行估计和补偿,然后在残余相位误差估计时利用STFT对时变信号进行滤波以提高信杂比(SCR)。仿真和实测数据的处理结果验证了该文算法的有效性。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.

关 键 词：合成孔径雷达 自聚焦 短时傅里叶变换 信杂比 二次相位误差 

分 类 号：TN959.73[电子电信—信号与信息处理]