Research on Noise Reduction Method of GNSS Deformation Monitoring Data
In order to improve the noise reduction effect of GNSS deformation monitoring data and extract useful information from the data as much as possible,a new LMD-EMD noise reduction method is proposed by combining local mean decomposition(LMD)method with empirical mode decomposition(EMD)method.The technical process of the combined noise reduction method to reduce the noise of GNSS monitoring data is as follows:first,the original GNSS monitoring data is decomposed by LMD method to obtain the product function(PF)components and residual terms of different frequency bands,and the Hust index of each component is calculat-ed to determine the dividing point of high-frequency component and low-frequency component;Secondly,the EMD method is used to further decompose the high-frequency components to obtain the intrinsic mode function(IMF)and residual terms in different frequen-cy bands.The dividing points of high-frequency components and low-frequency components are determined by calculating the multi-scale permutation entropy mean of each IMF component;Finally,the final de-noising signal is obtained by reconstructing the low-fre-quency components obtained from the two decomposition.The effectiveness of the proposed method is verified by using simulated sig-nals and measured GNSS monitoring data.The results show that compared with the single LMD method and EMD method,the com-bined noise reduction method proposed in this paper has higher accuracy and can accurately express the deformation trend of the origi-nal signal.
local mean decompositionempirical mode decompositionnoise reductionGNSS
NETL
NSTL
万方数据
