基于STFT和WT的SAR干扰抑制算法

Interference Suppression Algorithm for SAR Based on Short-Time Fourier Transform and Wavelet Transform

窄带干扰(NBI)和宽带干扰(WBI)作为合成孔径雷达(SAR)中最为常见的两种干扰形式,它们的存在将会大幅度地降低SAR图像的质量.本文在对NBI和WBI的时频聚集性分析的基础上,提出一种联合短时傅里叶变换和小波变换的NBI和WBI抑制方法.该方法首先把SAR回波数据变换到短时傅里叶谱域再把短时傅里叶谱域数据变换到小波域,然后在小波域中采用恒虚警(CFAR)检测方法对小波系数进行干扰识别和干扰抑制,接着把干扰抑制后的小波系数变换到SAR原始回波数据域,利用常规的SAR成像算法进行成像处理,最后得到清晰无干扰的SAR图像.该算法在干扰抑制过程中对有用回波信号造成的损失比较小,并且可以有效地抑制时变的NBI和WBI.结合仿真和实测数据的处理,经过实验分析验证了本文方法的有效性.

As the two most common forms of interference in synthetic aperture radar（SAR）.Narrow-band interference（NBI） and wide-band interference（WBI） significantly reduce the quality of SAR images.Based on the analysis of the time-frequency concentration of NBI and WBI,an interference suppression algorithm for SAR is proposed.In the algorithm,SAR echo data is transformed into the short time Fourier transform spectrum domain,and then it is transformed into the wavelet domain.In the wavelet domain,the constant false alarm rate（CFAR） algorithm is employed to operate interference identification and suppression.After that,a clear and noninterference SAR image can be obtained by using a conventional SAR imaging algorithm.This algorithm brings less loss to useful data during interference suppression,and can efficiently suppress the time-varying NBI and WBI.The processing results of the simulation and the real measured data prove the effectiveness of this alaorithm.