CAJ | 학술논문

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。
단시부리협변환(Short-Time Fourier Transform, STFT)시연구비평은신호최위엄범사용적중요방법。해문재토론료이용STFT대선성조빈신호(LFM)진행려파이급조빈솔고계후，제출일충기우STFT적궤재SAR자취초산법。해산법수선이용STFT대영향SAR도상질량적주요상위오차이차상위오차(QPE)진행고계화보상，연후재잔여상위오차고계시이용STFT대시변신호진행려파이제고신잡비(SCR)。방진화실측수거적처리결과험증료해문산법적유효성。
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.