非参数化迭代自适应SAR射频干扰抑制方法

Non-parametric iterative adaptive radio frequency interference suppression approach for SAR systems

合成孔径雷达(Synthetic Aperture Radar,SAR)的成像质量与图像解译精度会因为空间中存在的射频干扰(Radio Frequency Interference,RFI)而下降。本文在加权最小二乘迭代自适应算法的基础上,提出了非参数化的迭代自适应RFI抑制方法。该方法在成像处理前增加了对RFI的预检测环节,在初步检测出存在RFI的数据部分后只对存在RFI的数据进行SG(Savitsky-Golay,萨维茨基·戈莱)卷积平滑处理以提升对弱RFI的检测能力。利用带阻滤波器滤除存在干扰的频段后,使用迭代自适应处理在频谱中估计出被去除频段中的信号分量以获得期望的距离谱。与利用传统距离频率滤波方法进行RFI抑制相比,所提出的方法在图像细节保持方面效果更优,避免了因频谱不连续而导致的旁瓣增加,且运算效率更高。

The image quality and image interpretation accuracy of Synthetic Aperture Radar(SAR)deteriorates due to the presence of Radio Frequency Interference(RFI)in space.Based on the weighted least squares iterative adaptive algorithm,a nonparametric iterative adaptive RFI suppression is proposed.The proposed approach supplements a pre-detection step for RFI before imaging processing.After the initial detection of data with RFI,only the data with RFI is subjected to SG(Savitsky-Golay)convolutional smoothing to improve the detection ability of weak RFI.After filtering out the interfering bands by using a band-reject filter,iterative adaptive processing is employed to estimate the signal components of the removed bands to obtain the desired spectrum in the range direction.Compared with the traditional filtering approach for RFI suppression in range frequency domain,the proposed approach is more effective in image detail preservation,avoiding the increase of side lobes caused by spectral discontinuity,and has higher computational efficiency.