Denoising method for ground-space electromagnetic data based on exponential fitting-adaptive Kalman

Abstract

The invention relates to an exponential fit-adaptive Kalman-based ground-air electromagnetic data de-noising method. According to the technical scheme of the invention, for single-point electromagnetic data during the ground-air measurement, time windows are determined and then the data are segmented at equal logarithm interval based on the features of electromagnetic data in the ground-air time domain according to the approximate e-index attenuation law, and the time constant value of data in each time frame are extracted as fitting parameters. Meanwhile, the data in each time frame are processed based on the e-exponential fitting method, and fitting output results are adopted as predicted values to be input into a filter. After that, the adaptive scalar Kalman filtering method is applied to filtering the electromagnetic noise in data, and the filtered data are subjected to resistivity-depth imaging. Compared with the existing electromagnetic data filtering method in the ground-air time domain, the above filtering method of the present invention not only effectively suppresses the electromagnetic noise in electromagnetic data in the ground-air time domain, but also fully retains and enhances the effective information in measured data. Therefore, both the signal-to-noise ratio and the quality of electromagnetic data in the ground-air time domain are improved.

Description

technical field [0001] The invention relates to a time-domain electromagnetic data filtering method, which is suitable for electromagnetic data filtering conforming to the e-exponential attenuation law, and is especially suitable for ground-space time-domain electromagnetic data filtering. Background technique [0002] Ground-airborne Time-domain electromagnetic system (GATEM for short) uses long wire sources laid on the ground to emit bipolar pulse currents to excite the ground, forming large-area electromagnetic waves in space, and using drones in the air Or the airship carries a receiving coil to collect the magnetic field response. The ground-space time-domain electromagnetic method combines the advantages of ground transient electromagnetic and airborne time-domain electromagnetic. This method not only has the advantages of high efficiency and strong ability to deal with complex terrain compared with the ground transient electromagnetic system, but also has better spat...

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Problems solved by technology

[0006] CN201110197887.4 discloses a long wire source transient electromagnetic ground-air detection method and a processing and interpretation method, but does not provide a filtering method for ground-air detection data; CN201510193706.9 discloses an aeronautical denoising method for aeronautical electromagnetic signals Although the method of mathematical morphology can be used to denoise the ground-to-air electromagnetic detection data to remove positive and negative pulse noise and random noise in the signal, the actual ground-to-space electromagnetic detection data also contains white noise, Electromagnetic noise such as power frequency interference, engine, motion, etc., are mixed and difficult to separate

At present, most of the denoising methods for ground-air electromagnetic detection data can effectively remove a certain type of electromagnetic noise, but they do not consider the characteristics of ground-space electromagnetic signals, resulting in the change of the attenuation curve characteristics when there is large noise interference.

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