基于EMD和伪Wigner-Ville分布的大地电磁信号功率谱估计  

Power spectrum estimation of MT signal based on EMD and fake Wigner-Ville

作　　者：蔡剑华[1] CAI JianHua(Cooperative Innovation Center for the Construction and Development of Dongting Lake Ecological Economic Zone,Hunan University of Arts and Science,Changde 415000,China)

机构地区：[1]湖南文理学院洞庭湖生态经济区建设与发展协同创新中心,常德415000

出　　处：《地球物理学进展》2021年第6期2433-2440,共8页Progress in Geophysics

基　　金：国家自然科学基金项目(41304098);湖南省自然科学基金项目(2021JJ30469);湖南省教育厅重点项目(16A146)“光电信息集成与光学制造技术”湖南省级重点实验室联合资助。

摘　　要：为了减小大地电磁信号的非平稳性给谱估计带来的偏差,本文从时-频域上,提出了一种基于EMD和伪Wigner-Ville分布的大地电磁信号功率谱估计方法.将MT信号的幅度表示为频率和时间的函数,然后从时间-频率谱中统计估算功率谱,并引进EMD和伪Wigner-Ville分布来抑制Wigner-Ville分布中的交叉项.文章讨论了新方法求得的功率谱的物理意义,并与传统方法进行了比较.结果表明,本文方法为减小信号非平稳性带来的谱估算偏差提供了一种新思路,可以获得稳健的MT信号功率谱,为进一步的阻抗估计奠定了良好的基础.In order to reduce the bias caused by the non-stationarity of Magnetotelluric(MT)signals,a power spectrum estimation method based on EMD and fake Wigner-Ville distribution is proposed in this paper.Firstly,the amplitude of MT signal is expressed as a function of frequency and time,then the power spectrum is estimated from the time-frequency spectrum.EMD and fake Wigner-Ville distribution are introduced to suppress the cross terms in Wigner-Ville distribution.The physical meaning of the power spectrum obtained by this method is discussed and compared with the traditional method.The results show that this method provides a new idea to reduce the spectral estimation error caused by the non-stationarity of the signal,and stable power spectral estimation of MT signal can be obtained,it lays a good foundation for the further research of impedance estimation and source structure.

关 键 词：时频法 功率谱估计 大地电磁信号 经验模态分解 伪Wigner-Ville 

分 类 号：P631[天文地球—地质矿产勘探]