基于小波变换的射频干扰消除方法的研究

Study of Radio Frequency Interference Mitigation Method Based on Wavelet Transform

在射电天文观测中,射频干扰(Radio Frequency Interference,RFI)会以多种形式混入望远镜接收系统,给观测带来误判或者降低观测信噪比.近年来国内国际射电天文快速发展,国内国际大型射电望远镜和阵列先后建设,观测灵敏度大为提高,射频干扰的影响尤为突出.随着科技发展和人类活动的加剧,射频干扰日益严重且不可逆转.提出利用2维离散小波变换的方法分析射电天文观测的数据,对望远镜系统输出的时间频率序列进行小波变换,根据小波系数分离出原始信号中各分量,每个分量统计得到相应的阈值,将各分量与阈值相比较识别干扰成分并标记去除.利用该方法对实际观测数据进行了处理,结果表明该方法能够很好地标记并消减干扰信号,且提高了观测的信噪比.

In radio astronomy observations,radio frequency interference(RFI)is mixed into the telescope receiving system in various forms.The existence of RFI brings misjudgment to the observation or reduces the observation signal-to-noise ratio.In recent years,domestic and overseas radio astronomy has developed rapidly.Large-scale radio telescopes or arrays of large telescopes at home and abroad have been constructed successively.Observation sensitivity is greatly improved,and the influence of RFI is particularly prominent.With the development of science and technology and the intensification of human activities,RFI has become increasingly serious and irreversible.We propose to use the two-dimensional discrete wavelet transform method to analyze the data of radio astronomy observations,and to perform wavelet transform on the time-frequency sequence output by the telescope system.According to the wavelet coefficients,each component in the original signal is separated,and the corresponding threshold value is obtained by statistics of each component.Each component is compared with a threshold to identify the interference component and mark it for removal.This method is used to process the actual observation data.The results show that this method can well mark and eliminate the interference signal,and improve the observed signal-to-noise ratio.