利用小波变换进行合成孔径雷达窄带干扰抑制算法

SAR interference suppression algorithm for narrow band interference via wavelets

在对窄带干扰(NBI)进行时频特性分析的基础上,提出了一种利用小波变换进行NBI抑制的方法.该方法首先把回波数据的频谱变换到多分辨的小波域中;然后在小波域中采用恒虚警概率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数据变换到原始回波数据域,利用常规的SAR成像算法进行成像处理;最后得到清晰的SAR图像.与其他窄带干扰抑制算法相比,该算法在干扰抑制过程中对有用信号造成的损失较小,并且可以有效地抑制时变的NBI.结合仿真和实测数据的处理,经过实验分析,验证了该方法的有效性.

The presence of Narrow-band interference （NBI） usually degrades the imaging quality dramatically, Based on the time-frequency feature analysis of NBI, a new NBI suppression algorithm is proposed by the use of the wavelets transform in this paper. In this algorithm, the spectrum of the echo corrupted by NBI is transformed into the multi-resolution wavelet domain. Then the NBI components can be identified and subsequently filtered out while preserving the useful signal as much as possible at the constant-false-alarm-rate. After that, the data after NBI suppression are transformed into the original echo domain. Finally, weU-focused SAR imagery can be obtained from the echoes without NBI by the traditional SAR imaging algorithm. The loss of the useful signal data during the operation is smaller than that by the other NBI suppression algorithm. In addition, this algorithm is robust to time-varying NBI. Imaging results of both simulation data and measured data have proved the validity of this algorithm.