Stady On Airborne Transient Electromagnetic Method Of Denoising Based On Empirical Mode Decomposition And Independent Component Analysis

This article is based on the subject of "National Aerospace Geophysical Technology Demonstration and Processing and Interpretation Software Platform Development in Typical Coverage Areas","Research on Aeronautical Geophysical Data Comprehensive Processing and Interpretation Methods and Software Development"(Project No: 2017YFC0602202).And the suppression method of power frequency noise was studied.Aeronautical transient electromagnetic method is an important direction for the development of transient electromagnetic method in recent years.Due to its high efficiency,labor saving and strong terrain adaptability,it can be difficult to enter in humans,such as mountains and deserts.Lakes and swamps,forest cover and other places with poor topographic conditions and complex geological environment to conduct convenient and fast exploration.However,since the aviation transient electromagnetic method uses an aircraft as a carrier,its measured data is extremely susceptible to noise interference.Therefore,in order to improve the interpretation and accuracy of subsequent inversion calculations,it is necessary to strengthen the research on noise suppression of aviation transient electromagnetic data.Although there are many kinds of methods for aviation transient electromagnetic denoising,there is still a lack of better denoising methods.To this end,this paper will deal with the electromagnetic noise encountered in the process of aviation transient electromagnetic measurement based on the two theories of empirical mode decomposition(EMD)and independent component analysis(ICA),in order to greatly improve the aviation transient electromagnetic data Signal-to-noise ratio.In this paper,first of all,through the summary analysis of empirical mode decomposition theory and independent component analysis theory,the combination point of these two methods is drawn,and then the basic method of joint denoising is given to explore its effect on noise in aviation transient electromagnetic data Suppress the effect,and give the corresponding denoising process,that is,decompose the aviation transient electromagnetic signal into multiple IMFs through EMD,and then determine the boundary between noise and signal of the decomposed IMF according to the relevant criteria,and finally reconstruct The noise and noisy signal are used as the input of ICA to achieve the purpose of removing noise.In order to illustrate the effect of denoising,the noise interference simulation was performed on the 1D and 3D forward aeronautical transient electromagnetic data,and the combined method of EMD and EMD-ICA was used to denoise the forward data with noise.Whether it is random noise or power frequency interference,or a mixture of the two,the denoising effect of the EMD-ICA method should be significantly better than the EMD denoising method.Finally,a line in the aeronautical transient electromagnetic measurement data of a place in Qinling is denoised by EMD-ICA method.Through the comparison before and after denoising,it is concluded that the EMD-ICA method can be well achieved in the measured data.The purpose of noise preservation.It fully illustrates the applicability of this method in the preprocessing of aviation transient electromagnetic data.