呼和浩特轨道交通对地磁数据的干扰特征及去噪方法

Interference Characteristics and Denoising Method for the Noise of Geomagnetic Data Caused by Rail Transit in Hohhot

通过分析地铁供电系统的组成架构,对呼和浩特地磁台的干扰机理进行分析阐述,总结干扰的基本特征;同时,结合小波变换的方法获得地铁干扰的频带范围及频谱特征,获取时频联合域中能量密度分布。在此基础上采用BD小波分解方法对高频干扰部分进行滤除,达到有效提高地磁观测质量的目的。

With the development and construction of urbanization and the increase of population density in Hohhot,the Hohhot subway was officially put into operation in January 2020,which immediately caused serious high-frequency noise interference to the original waveform produced by Hohhot geomagnetic station.As a result,the effective utilization rate of geomagnetic data is greatly reduced.Through the analysis of the basic principle of the subway power supply system,the interference mechanism caused by the geomagnetic station is analyzed,and the basic characteristics of the interference are summarized.We also analyzed the frequency band range and spectrum characteristics of the subway interference by the method of wavelet transform.The energy density distribution in time-frequency domain is obtained.On this basis,BD wavelet decomposition method is applied to filter the interference frequency band,so as to effectively improve the quality of geomagnetic observation.