研究了合成孔径雷达中的线性调频（LFM）信号的参数估计问题。分析和比较了常用的LFM分析算法的优缺点，提出了一种基于分数阶傅里叶变换和相位解缠的综合方法，提高了估计的有效性和鲁捧性。在计算机仿真中，采用该方法的估计参数对畸变LFM信号进行相位补偿和脉冲压缩，获得了令人满意的分析结果，验证了该方法的有效性和鲁棒性。最后，分析了LFM信号各阶分数阶傅里叶变换的特性，优化了分数阶傅里叶变换扫描算法，大大缩短了运算时间。

Linear Frequency Modulation(LFM) signal is transmitted by Synthetic Aperture Radar(SAR).And the accuracy of the LFM signal is vital to get high quality image in SAR system.This paper focuses on parameter estimation for LFM signal with noise.In it,a synthesized method of LFM signal analysis based on Fraction Fourier Transform(FRFT) and phase unwrapping is given.Compared with other methods,this method is more effective and robustness.And the results of experiment validate the high effectiveness and robust ness of the method.At last,by analyzing the characteristics of the FRFT of LFM signal, we improved the FRFT scan algorithm,and significantly shortened the run time.

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