Method, device, electronic device and storage medium for suppressing interference from magnetotelluric detection

Abstract

The present invention provides a method, device, electronic device, and storage medium for suppressing interference in magnetotelluric sounding, which are applied to magnetotelluric sounding systems and relate to the field of data processing technology. The method comprises: decoding raw magnetotelluric sounding data; wherein the decoded raw data comprises electric field data and magnetic field data; performing noise reduction processing on the decoded raw data; wherein the noise reduction processing comprises filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference, and subtracting the amplitude-phase-frequency response of the equipment; after normalizing the noise-reduced raw data, performing impedance estimation to determine parameters corresponding to the raw magnetotelluric sounding data; wherein the parameters comprise at least one of the following: impedance tensor, apparent resistivity, impedance phase, and dipole information; and through multiple noise reduction methods, improving the amplitude and phase reliability of the signal at the natural electromagnetic field analysis frequency, thereby improving the impedance estimation accuracy.

Description

Technical Field

[0001] The present invention relates to the field of data processing technology, and in particular to a method, device, electronic equipment and storage medium for suppressing interference in magnetotelluric detection. Background Art

[0002] When estimating impedance from magnetotelluric sounding, the amplitude and phase of the electromagnetic field response at a series of frequency points must be calculated segmentally in the acquired time-domain data. The apparent resistivity and impedance phase at each frequency point are then obtained using methods such as least squares or robust estimation (ROBUST). However, because natural electromagnetic field signals are non-periodic, random, broadband, and weak, they are susceptible to interference from environmental and human electromagnetic fields, which affects the impedance estimation accuracy of the observed data. Furthermore, during the spectrum analysis and processing of time series data, they are also highly susceptible to interference from low-frequency trends in the magnetotelluric field below the processing frequency and low-frequency drift interference from the instrument itself. This reduces the reliability of the amplitude and phase of the signal at the natural electromagnetic field analysis frequency, ultimately affecting the impedance estimation accuracy. Summary of the Invention

[0003] The purpose of the present invention is to provide a method, device, electronic device and storage medium for suppressing interference in magnetotelluric detection, which improves the amplitude and phase reliability of signals at the natural electromagnetic field analysis frequency through multiple noise reduction means, thereby improving the impedance estimation accuracy.

[0004] In a first aspect, the present invention provides a method for suppressing interference in magnetotelluric detection, which is applied to a magnetotelluric sounding system. The method comprises:

[0005] Decoding the raw data of magnetotelluric sounding; wherein the decoded raw data includes electric field data and magnetic field data;

[0006] Perform noise reduction processing on the decoded raw data; the noise reduction processing includes: filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference, and deducting the amplitude, phase, and frequency response of the equipment;

[0007] After normalizing the raw data after noise reduction, impedance estimation is performed to determine the parameters corresponding to the raw data of magnetotelluric sounding; wherein the parameters include at least one of the following: impedance tensor, apparent resistivity, impedance phase and dipole information.

[0008] In some preferred embodiments of the present invention, the step of performing noise reduction processing on the decoded original data includes:

[0009] The decoded original data is filtered to remove the power frequency interference wave of the preset frequency and the harmonics of the power frequency interference wave to obtain the first intermediate data.

[0010] In some preferred embodiments of the present invention, the step of performing noise reduction processing on the decoded original data further includes:

[0011] The DC component of the first intermediate data is determined based on an arithmetic mean method; wherein the DC component is constrained by the following formula:

[0012] ;

[0013] Among them, sp is the DC component, N t is the length of the first intermediate data, X1(i) is the time series of the original data;

[0014] The DC component is eliminated from the first intermediate data to obtain second intermediate data.

[0015] In some preferred embodiments of the present invention, the step of performing noise reduction processing on the decoded original data further includes:

[0016] Perform cumulative moving average on the data samples in the second intermediate data to obtain low-frequency trend interference; wherein the low-frequency trend interference is constrained by the following formula:

[0017] ;

[0018] Among them, f(j) is the low-frequency trend interference, N1 is the length of the second intermediate data, N t is the length of the first intermediate data;

[0019] The low-frequency trend interference is eliminated from the second intermediate data to obtain the third intermediate data.

[0020] In some preferred embodiments of the present invention, the step of performing noise reduction processing on the decoded original data further includes:

[0021] Performing Fourier transform on the third intermediate data to obtain third intermediate data in the frequency domain;

[0022] The third intermediate data in the frequency domain is deducted from the device amplitude, phase and frequency response to obtain the original data after noise reduction; wherein the device impact includes at least one of the following: the impact of the electromagnetic sensor, the amplitude impact of the receiver channel and the impact of the phase and frequency response.

[0023] In some preferred embodiments of the present invention, after normalizing the raw data after noise reduction, performing impedance estimation to determine the parameters corresponding to the raw data of magnetotelluric sounding includes: determining the impedance tensor using the following formula:

[0024] ;

[0025] ;

[0026] Among them, Ex is the component of the electric field data on the x-axis, Ey is the component of the electric field data on the y-axis, and H x is the component of the magnetic field data on the x-axis, H y is the component of the magnetic field data on the y-axis, Z xx is the first impedance tensor, Z xy is the second impedance tensor, Z yx is the third impedance tensor, Z yy is the fourth impedance tensor.

[0027] In some preferred embodiments of the present invention, after normalizing the raw data after noise reduction, performing impedance estimation and determining the parameters corresponding to the raw data of magnetotelluric sounding include: determining the dipole information by the following formula:

[0028] ;

[0029] Among them, H x is the component of the magnetic field data on the x-axis, H y is the component of the magnetic field data on the y-axis, H z is the component of the magnetic field data on the z axis, T zx is the first tilt information, T zy It is the second tilt information.

[0030] In a second aspect, the present invention provides a device for suppressing interference in magnetotelluric detection, which is applied to a magnetotelluric sounding system. The device comprises:

[0031] A data decoding module is used to decode and process the raw data of magnetotelluric sounding; wherein the decoded raw data includes: electric field data and magnetic field data;

[0032] The data noise reduction module is used to perform noise reduction processing on the decoded raw data; the noise reduction processing includes: filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference, and deducting the amplitude, phase, and frequency response of the equipment;

[0033] The impedance determination module is used to perform impedance estimation on the raw data after normalization of the noise reduction, and determine the parameters corresponding to the raw data of the magnetotelluric sounding; wherein the parameters include at least one of the following: impedance tensor, apparent resistivity, impedance phase and dipole information.

[0034] In a third aspect, the present invention provides an electronic device comprising a processor and a memory, wherein the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement the method for suppressing interference from magnetotelluric detection provided in the first aspect.

[0035] In a fourth aspect, the present invention provides a storage medium storing computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the method for suppressing interference from magnetotelluric detection provided in the first aspect.

[0036] The present invention brings the following beneficial effects:

[0037] The present invention provides a method, device, electronic device and storage medium for suppressing interference in magnetotelluric detection, which are applied to a magnetotelluric sounding system. The method comprises: decoding raw data of magnetotelluric sounding; wherein the decoded raw data comprises electric field data and magnetic field data; performing noise reduction processing on the decoded raw data; wherein the noise reduction processing comprises filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference and subtracting the amplitude-phase-frequency response of the equipment; performing impedance estimation after normalizing the raw data after noise reduction to determine parameters corresponding to the raw data of magnetotelluric sounding; wherein the parameters comprise at least one of the following: impedance tensor, apparent resistivity, impedance phase and dipole information; and through multiple noise reduction means, improving the amplitude and phase reliability of the signal at the natural electromagnetic field analysis frequency, thereby improving the impedance estimation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 A flow chart of a method for suppressing interference in magnetotelluric detection provided by an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of an electric field data curve provided by an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of an electric field data curve after filtering out 50 Hz and its harmonic interference provided by an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of an electric field data curve after removing the DC component provided by an embodiment of the present invention;

[0043] Figure 5 A schematic diagram of a low-frequency trend electric field data curve with an analysis period greater than 2 seconds provided by an embodiment of the present invention;

[0044] Figure 6A schematic diagram of time series data after removing low-frequency trend interference provided by an embodiment of the present invention;

[0045] Figure 7 A schematic diagram of a magnetotelluric depth apparent resistivity curve and an impedance phase data curve provided by an embodiment of the present invention;

[0046] Figure 8 A schematic structural diagram of a device for suppressing interference in magnetotelluric detection provided by an embodiment of the present invention;

[0047] Figure 9 A schematic structural diagram of an electronic device provided by an embodiment of the present invention.

[0048] Icons: 310 - data decoding module; 320 - data noise reduction module; 330 - impedance determination module; 400 - memory; 401 - processor; 402 - bus; 403 - communication interface. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0050] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0051] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0052] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like indicate positions or locations based on the positions shown in the accompanying drawings, or the positions or locations in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0053] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0054] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0055] Magnetotelluric sounding, a method for probing the electrical structure of Earth's interior at great depths, was proposed in the 1950s and has gradually matured. It incorporates high-resolution electromagnetic field sensors, wide-dynamic-range receivers, high-precision impedance estimation, and forward and inversion interpretation techniques. The source of magnetotelluric sounding is a naturally occurring, regionally distributed alternating electromagnetic field. Its signal has a wide bandwidth (n×10kHz to 0.00001Hz) and a large penetration depth, making it an important geophysical method for probing the electrical structure of the Earth's crust and upper mantle.

[0056] Estimating impedance in magnetotelluric sounding requires calculating the amplitude and phase of the electromagnetic field response at a series of frequency points in the acquired time-domain data. The apparent resistivity and impedance phase at each frequency point are then obtained using methods such as least squares or robust estimation (ROBUST). However, because natural electromagnetic field signals are non-periodic, random, broadband, and weak, they are susceptible to interference from environmental and human electromagnetic fields, which affects the impedance estimation accuracy of the observed data. Furthermore, during spectral analysis of time series data, they are also highly susceptible to low-frequency trend interference from the magnetotelluric field below the processing frequency and low-frequency drift interference from the instrument itself. This reduces the reliability of the amplitude and phase of the signal at the natural electromagnetic field analysis frequency, ultimately affecting the impedance estimation accuracy. Numerous experts and scholars have studied environmental and human electromagnetic field interference in magnetotelluric sounding, achieving fruitful results. However, the impact of low-frequency trend interference from the magnetotelluric field and low-frequency drift interference from the instrument itself has received insufficient attention, resulting in reduced impedance estimation accuracy from magnetotelluric observation data and hindering its practical application. This presents a difficult issue that needs to be addressed in magnetotelluric sounding data processing.

[0057] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0058] Example 1

[0059] The present invention provides a method for suppressing interference in magnetotelluric detection, which is applied to magnetotelluric sounding system. Figure 1 The flowchart of a method for suppressing interference in magnetotelluric detection provided by an embodiment of the present invention is shown, and the method includes:

[0060] Step S102 : decoding the original data of the magnetotelluric sounding; wherein the decoded original data includes electric field data and magnetic field data.

[0061] Specifically, suppose the sampling rate of a certain frequency band data collected by a certain channel of the magnetotelluric sounder is , the sampling time series is The total acquisition time is ; Assume that the longest cycle to be processed is , the number of sample points is , . is the period at the frequency to be analyzed.

[0062] Generally speaking, magnetotelluric sounding collects data in multiple frequency bands. For time series data collected continuously in a certain frequency band, they need to be processed in blocks, requiring the time length of each block of data to be at least 6 times the length of the processing period (the purpose is to reduce the impact of the truncation effect of spectrum analysis). At the same time, at least 3 or more independent blocks of data are required for analysis and superposition processing to eliminate the influence of random interference. In actual data collection, the data length must be much longer than 18 times (6×3) the minimum analysis period of the frequency band.

[0063] Decode the raw data of magnetotelluric sounding observed in the field. The raw data of magnetotelluric sounding observed in the field can include 4 components E x 、E y 、H x 、H y or 5 parts E x 、E y 、H x 、H y 、H z , converted into decimal electric field data (unit: mV) or magnetic field data (unit: mV); it should be emphasized that, in the embodiment of the present invention, the x-axis is an identifier of a specified direction during measurement, the y-direction is perpendicular to the x-direction, and the z-direction is perpendicular to the xy plane; in some preferred embodiments of the present invention, the x-axis is the north-south direction.

[0064] For example, see Figure 2 The diagram shows a schematic diagram of an electric field data curve provided by an embodiment of the present invention, which shows a segment of an electric field data curve of magnetotelluric sounding observed at a certain location, with a sampling rate of 0.002 seconds.

[0065] Step S104 , performing noise reduction processing on the decoded original data; wherein the noise reduction processing includes: filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference, and subtracting the amplitude-phase-frequency response of the equipment.

[0066] Specifically, in some preferred embodiments of the present invention, the step of performing noise reduction processing on the decoded original data includes: filtering out the power frequency interference wave of a preset frequency and harmonics of the power frequency interference wave from the decoded original data to obtain first intermediate data.

[0067] Specifically, digital filtering and other methods are used on the decoded electric and magnetic field data to suppress 50 Hz and its harmonic power frequency interference. This 50 Hz and its harmonic power frequency interference is a common source of electromagnetic interference encountered in magnetotelluric sounding (domestic power grids are 50 Hz, while foreign power grids are mostly 60 Hz). This interference seriously affects the accuracy of the processing results and must be eliminated during preprocessing.

[0068] Continue to see Figure 2 The magnetotelluric field collected in the field is subject to strong power frequency interference of 50Hz and its harmonics. It is difficult to identify the effective signal from the curve. After digital filtering, see Figure 3 The diagram shown is a schematic diagram of an electric field data curve after filtering out 50 Hz and its harmonic interference provided by an embodiment of the present invention, which shows that the power frequency interference of 50 Hz and its harmonics has been suppressed.

[0069] Furthermore, in some preferred embodiments of the present invention, the step of performing noise reduction processing on the decoded original data further includes: determining a DC component of the first intermediate data based on an arithmetic mean method; wherein the DC component is constrained by the following formula: Where sp is the DC component, N t is the length of the first intermediate data, X1(i) is the time series of the original data; the DC component is eliminated from the first intermediate data to obtain the second intermediate data.

[0070] Specifically, the arithmetic mean method is used to eliminate the DC component of the observed data for the filtered electric and magnetic field data, and the resulting time series is: The original observation data length is N. After digital filtering suppresses the power frequency interference of 50 Hz and its harmonics, the remaining data length is , whose length is less than the original observation data length N. The DC component is constrained by the following formula: . ; Among them, sp is the DC component, N t is the length of the first intermediate data, X1(i) is the time series of the original data, and z(i) is the second intermediate data after removing the DC component. Figure 4 The figure shows a schematic diagram of an electric field data curve after removing the DC component provided by an embodiment of the present invention.

[0071] Furthermore, in some preferred embodiments of the present invention, the step of performing noise reduction processing on the decoded original data further includes: performing cumulative moving average on the data samples in the second intermediate data to obtain low-frequency trend interference; wherein the low-frequency trend interference is constrained by the following formula:

[0072] Among them, f(j) is the low-frequency trend interference, N1 is the length of the second intermediate data, N t is the length of the first intermediate data; the low-frequency trend interference is eliminated from the second intermediate data to obtain the third intermediate data.

[0073] Specifically, magnetotelluric time-series data contain both broadband, random natural electromagnetic field signals and various human-induced electromagnetic interference (e.g., power frequency interference primarily consisting of 50 Hz and its harmonics, high-speed rail, photovoltaic power generation, wind power generation, highways, and communications), as well as noise and drift from the measuring instruments themselves. In data processing, in addition to suppressing the effects of these human-induced electromagnetic interference, it is also necessary to suppress the influence of natural electromagnetic field trend signals below the processing period and the instrument's own drift interference. This is necessary to obtain more accurate natural electromagnetic field amplitude and phase at the processing period for subsequent estimation of the magnetotelluric impedance tensor. Natural electromagnetic field signals are inherently broadband and random, with significant signal strength variations (up to 120 dB) at different frequencies (or periods). Furthermore, time-series data collected in the field are of finite length. Without suppressing signals below the processing period, the signal amplitude and phase at the processing period will be severely distorted during time-to-frequency conversion.

[0074] When processing a certain frequency band or a certain block of observation data, the processing cycle is (or frequency , ), the corresponding observation data length is When the suppression cycle is greater than the analysis cycle The influence of low-frequency trend interference on the processed data is firstly The data samples are accumulated and moved averaged to form a new time series ,Right now: ; The period in this block of data is greater than That is to say, this method can separate the low-frequency trend interference from the observation data, and the time series minus , generate a new time series ,Right now: ; ; ; , That is, the time series data after removing low-frequency trend interference.

[0075] For example, the sampling rate of the frequency band data is 0.002 seconds, see Figure 5 The embodiment of the present invention shown in FIG. 1 provides a schematic diagram of a low-frequency trend electric field data curve with an analysis period greater than 2 seconds. The curve is a low-frequency trend interference time series data separated by the above method; see FIG. Figure 6 The embodiment of the present invention provides a schematic diagram of a time series data after removing low-frequency trend interference. The curve is an electric field data curve with a period of less than or equal to 2 seconds. In actual use, the data sampling rate is , data length N, analysis period (The corresponding data length ) are variable and can be adjusted according to the actual observation data.

[0076] Furthermore, in some preferred embodiments of the present invention, the step of performing noise reduction processing on the decoded original data also includes: performing Fourier transform on the third intermediate data to obtain third intermediate data in the frequency domain; subtracting the amplitude, phase and frequency response of the device from the third intermediate data in the frequency domain to obtain the noise-reduced original data; wherein the device influence includes at least one of the following: the influence of the electromagnetic sensor, the amplitude influence of the receiver channel and the influence of the phase and frequency response.

[0077] Specifically, the four components (E x 、E y 、H x 、H y ) or 5 components (E x 、E y 、H x 、H y 、H z ) data is Fourier transformed from the time domain to the frequency domain, and the amplitude, phase and frequency responses of the electromagnetic sensor and receiver channels are deducted.

[0078] Magnetic field sensors have different amplitude and phase responses at different frequencies. For example, at a frequency of 1000Hz, a magnetic field sensor has an amplitude response of 100mV / nT and a phase response of -20 degrees; however, at 0.1Hz, its amplitude response is 20mV / nT and its phase response is 120 degrees. Similarly, receiver channels have different amplitude and phase responses at different frequencies. In this case, it is necessary to deduct the amplitude and phase frequency response base to obtain the true amplitude and phase of the natural electromagnetic field at a specific frequency.

[0079] Step S106 , after normalizing the raw data after noise reduction, impedance estimation is performed to determine parameters corresponding to the raw data of magnetotelluric sounding; wherein the parameters include at least one of the following: impedance tensor, apparent resistivity, impedance phase and dipole information.

[0080] Specifically, the raw data after noise reduction in the above steps are normalized to electric field data (unit: mV / km) and magnetic field data (unit: nT), and conventional impedance estimation methods such as least squares method and robust estimation method can be used to obtain the impedance tensor of the magnetotelluric at different periods (or frequencies) with basically logarithmic equal interval distribution, as well as parameter information such as apparent resistivity, impedance phase and dipole.

[0081] Furthermore, in some preferred embodiments of the present invention, after normalizing the raw data after noise reduction, performing impedance estimation to determine the parameters corresponding to the raw data of magnetotelluric sounding includes: determining the impedance tensor using the following formula: ; ; Wherein, Ex is the component of the electric field data on the x-axis, Ey is the component of the electric field data on the y-axis, Hx is the component of the magnetic field data on the x-axis, Hy is the component of the magnetic field data on the y-axis, Zxx is the first impedance tensor, Zxy is the second impedance tensor, Zyx is the third impedance tensor, and Zyy is the fourth impedance tensor.

[0082] Furthermore, in some preferred embodiments of the present invention, after normalizing the raw data after noise reduction, performing impedance estimation and determining the parameters corresponding to the raw data of magnetotelluric sounding include: determining the dipole information using the following formula: Among them, H x is the component of the magnetic field data on the x-axis, H y is the component of the magnetic field data on the y-axis, H z is the component of the magnetic field data on the z-axis, Tzx is the first dipole information, and Tzy is the second dipole information.

[0083] Specifically, if only 4 components E are observed in the field x 、E y 、H x 、Hy , can only calculate the impedance tensor information, can not obtain the inclination information; when the observation has 5 components E x 、E y 、H x 、H y 、H z When , not only the impedance tensor information but also the dipole information can be obtained. The impedance tensor and dipole information are obtained by least squares method, and they are both related to frequency.

[0084] For example, see Figure 7 The figure shows a schematic diagram of the apparent resistivity curve and impedance phase data curve of magnetotelluric sounding provided by an embodiment of the present invention. The apparent resistivity and impedance phase data of magnetotelluric sounding obtained after processing by the method provided by an embodiment of the present invention have continuous and smooth data curves, which conform to the characteristics of magnetotelluric sounding data and can be directly used for inversion and interpretation, thereby improving the ability of magnetotelluric sounding to solve complex geological problems.

[0085] The method for suppressing interference in magnetotelluric detection provided by the present invention sequentially filters out power frequency interference, eliminates DC components, removes low-frequency trend interference, and deducts the amplitude-phase-frequency response of the equipment. This method can better separate and remove low-frequency trend interference, and improve the calculation accuracy of magnetotelluric impedance estimation and parameters such as apparent resistivity and impedance phase.

[0086] The present invention provides a method for suppressing interference in magnetotelluric sounding, which addresses the difficulty of reducing the impedance estimation accuracy and affecting its practical application effect due to the low-frequency trend interference of the aforementioned magnetotelluric sounding. The method is based on the low-frequency trend drift characteristics of the magnetotelluric field and the instrument itself. Starting from the observed discrete time series data, the low-frequency trend interference data is first separated by moving average; then the low-frequency trend interference data is subtracted from the original observation data. The remaining time series data is the magnetotelluric field data within the frequency range to be processed after the low-frequency trend interference is removed. This method is original in magnetotelluric sounding data processing and has the advantages of a simple and fast calculation method, low data loss, and small distortion. It can significantly suppress the impact of the low-frequency trend interference of magnetotelluric sounding on the accuracy of spectrum analysis, improve the accuracy of impedance estimation, and enhance the application effect of magnetotelluric sounding in solving practical geological problems.

[0087] The present invention provides a method for suppressing interference in magnetotelluric detection, which is applied to a magnetotelluric sounding system. The method comprises: decoding raw data of magnetotelluric sounding, wherein the decoded raw data comprises electric field data and magnetic field data; performing noise reduction processing on the decoded raw data, wherein the noise reduction processing comprises filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference, and subtracting the amplitude-phase-frequency response of the equipment; performing normalization processing on the raw data after noise reduction, and then performing impedance estimation to determine parameters corresponding to the raw data of magnetotelluric sounding, wherein the parameters comprise at least one of the following: impedance tensor, apparent resistivity, impedance phase, and dipole information; and through multiple noise reduction means, improving the amplitude and phase reliability of the signal at the natural electromagnetic field analysis frequency, thereby improving the impedance estimation accuracy.

[0088] Example 2

[0089] On the basis of the above embodiments, the present invention provides a device for suppressing interference of magnetotelluric detection, which is applied to magnetotelluric sounding system. Figure 8 The structure diagram of a device for suppressing interference in magnetotelluric detection provided by an embodiment of the present invention is shown, and the device includes:

[0090] The data decoding module 310 is used to decode the original data of magnetotelluric sounding; wherein the decoded original data includes electric field data and magnetic field data.

[0091] The data noise reduction module 320 is used to perform noise reduction processing on the decoded original data; wherein the noise reduction processing includes: filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference, and subtracting the amplitude-phase-frequency response of the equipment.

[0092] The impedance determination module 330 is used to perform impedance estimation on the raw data after normalization of the noise reduction, and determine the parameters corresponding to the raw data of the magnetotelluric sounding; wherein the parameters include at least one of the following: impedance tensor, apparent resistivity, impedance phase and dipole information.

[0093] Furthermore, in some preferred embodiments of the present invention, the data noise reduction module 320 is configured to filter out the power frequency interference wave of a preset frequency and harmonics of the power frequency interference wave from the decoded original data to obtain first intermediate data.

[0094] Furthermore, in some preferred embodiments of the present invention, the data noise reduction module 320 is further configured to determine a DC component of the first intermediate data based on an arithmetic mean method; wherein the DC component is constrained by the following formula: ; Among them, sp is the DC component, N t is the length of the first intermediate data, X1(i) is the time series of the original data; the DC component is eliminated from the first intermediate data to obtain the second intermediate data.

[0095] Furthermore, in some preferred embodiments of the present invention, the data noise reduction module 320 is further configured to perform a cumulative moving average on the data samples in the second intermediate data to obtain low-frequency trend interference; wherein the low-frequency trend interference is constrained by the following formula: ; Where f(j) is the low-frequency trend interference, N1 is the length of the second intermediate data, N t is the length of the first intermediate data; the low-frequency trend interference is eliminated from the second intermediate data to obtain the third intermediate data.

[0096] Furthermore, in some preferred embodiments of the present invention, the data noise reduction module 320 is also used to perform Fourier transform on the third intermediate data to obtain third intermediate data in the frequency domain; and subtract the amplitude, phase and frequency response of the device from the third intermediate data in the frequency domain to obtain the original data after noise reduction; wherein the device influence includes at least one of the following: the influence of the electromagnetic sensor, the amplitude influence of the receiver channel and the influence of the phase frequency response.

[0097] Furthermore, in some preferred embodiments of the present invention, the impedance determination module 330 is configured to determine the impedance tensor using the following formula: ; ; Wherein, Ex is the component of the electric field data on the x-axis, Ey is the component of the electric field data on the y-axis, Hx is the component of the magnetic field data on the x-axis, Hy is the component of the magnetic field data on the y-axis, Zxx is the first impedance tensor, Zxy is the second impedance tensor, Zyx is the third impedance tensor, and Zyy is the fourth impedance tensor.

[0098] Furthermore, in some preferred embodiments of the present invention, the tilt information is determined by the following formula: Among them, H x is the component of the magnetic field data on the x-axis, H y is the component of the magnetic field data on the y-axis, H z is the component of the magnetic field data on the z axis, T zx is the first tilt information, T zy It is the second tilt information.

[0099] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described magnetotelluric detection interference suppression device can refer to the corresponding process in the aforementioned embodiment of the magnetotelluric detection interference suppression method, and will not be repeated here.

[0100] Example 3

[0101] The embodiment of the present invention further provides an electronic device for executing the method for suppressing interference of magnetotelluric detection; Figure 9The structure diagram of an electronic device provided by an embodiment of the present invention is shown, and the electronic device includes a memory 400 and a processor 401, wherein the memory 400 is used to store one or more computer instructions, and the one or more computer instructions are executed by the processor 401 to implement the above-mentioned method for suppressing interference from magnetotelluric detection.

[0102] Further, Figure 9 The electronic device shown further includes a bus 402 and a communication interface 403 , and the processor 401 , the communication interface 403 and the memory 400 are connected via the bus 402 .

[0103] The memory 400 may include high-speed random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage. The communication connection between the system network element and at least one other network element is achieved through at least one communication interface 403 (which may be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. may be used. The bus 402 may be an ISA bus, a PCI bus, or an EISA bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 9 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0104] The processor 401 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in the processor 401 or by software instructions. The above processor 401 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in conjunction with the embodiments of the present invention can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in memory 400, and processor 401 reads the information in memory 400 and, in conjunction with its hardware, completes the steps of the method of the aforementioned embodiment.

[0105] An embodiment of the present invention also provides a storage medium storing computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the above-mentioned method for suppressing interference from magnetotelluric detection. The specific implementation can be found in the method embodiment and will not be repeated here.

[0106] The computer program product of the magnetotelluric detection interference suppression method, device and electronic device provided in the embodiments of the present invention includes a storage medium storing program code. The instructions included in the program code can be used to execute the method in the previous method embodiment. The specific implementation can be found in the method embodiment and will not be repeated here.

[0107] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working process of the system and / or device described above can refer to the corresponding process in the aforementioned method embodiment and will not be repeated here.

[0108] In addition, in the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0109] If the functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for suppressing interference in magnetotelluric detection, characterized in that: Applied to a magnetotelluric sounding system, the method comprises: Decoding the raw data of magnetotelluric sounding; wherein the decoded raw data includes electric field data and magnetic field data; The decoded raw data is subjected to noise reduction processing; wherein the noise reduction processing includes: filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference, and subtracting the amplitude, phase, and frequency response of the device; wherein the decoded raw data is subjected to filtering out the power frequency interference to obtain first intermediate data; the first intermediate data is subjected to eliminating the DC components to obtain second intermediate data; and data samples in the second intermediate data are subjected to cumulative moving average to obtain the low-frequency trend interference; The step of performing noise reduction processing on the decoded original data further includes: eliminating the low-frequency trend interference from the second intermediate data to obtain third intermediate data; performing Fourier transform on the third intermediate data to obtain the third intermediate data in the frequency domain; and subtracting the device influence from the third intermediate data in the frequency domain to obtain the original data after noise reduction; wherein the device influence includes at least one of the following: the influence of the electromagnetic sensor, the amplitude influence of the receiver channel, and the influence of the phase frequency response; wherein the low-frequency trend interference is constrained by the following formula: Wherein, f(j) is the low-frequency trend interference, N1 is the length of the second intermediate data, N t is the length of the first intermediate data; After normalizing the raw data after noise reduction, impedance estimation is performed to determine parameters corresponding to the raw data of magnetotelluric sounding; wherein the parameters include at least one of the following: impedance tensor, apparent resistivity, impedance phase and dipole information.

2. The method for suppressing interference in magnetotelluric detection according to claim 1, characterized in that: The step of performing noise reduction processing on the decoded original data comprises: The decoded original data is filtered to remove the power frequency interference wave of a preset frequency and the harmonics of the power frequency interference wave to obtain the first intermediate data.

3. The method for suppressing interference in magnetotelluric detection according to claim 2, characterized in that: The step of performing noise reduction processing on the decoded original data further includes: The DC component of the first intermediate data is determined based on an arithmetic mean method; wherein the DC component is constrained by the following formula: Wherein, sp is the DC component, N t is the length of the first intermediate data, X1(i) is the time series of the original data; The DC component is eliminated from the first intermediate data to obtain second intermediate data.

4. The method for suppressing interference in magnetotelluric detection according to claim 1, wherein: After normalizing the raw data after noise reduction, performing impedance estimation to determine the parameters corresponding to the raw data of magnetotelluric sounding includes: determining the impedance tensor using the following formula: E x =Z xx H x +Z xy H y ; E y =Z yx H x +Z yy H y ; Among them, E x is the component of the electric field data on the x-axis, E y is the component of the electric field data on the y-axis, H x is the component of the magnetic field data on the x-axis, H y is the component of the magnetic field data on the y-axis, Z xx is the first impedance tensor, Z xy is the second impedance tensor, Z yx is the third impedance tensor, Z yy is the fourth impedance tensor.

5. The method for suppressing interference in magnetotelluric detection according to claim 4, characterized in that: After normalizing the raw data after noise reduction, performing impedance estimation to determine the parameters corresponding to the raw data of magnetotelluric sounding, the step includes: determining the tilt sub-information by the following formula: H z =T zx H x +T zy H y ; Among them, H x is the component of the magnetic field data on the x-axis, H y is the component of the magnetic field data on the y-axis, H z is the component of the magnetic field data on the z-axis, T zx is the first tilt information, T zy It is the second tilting sub-information.

6. A device for suppressing interference in magnetotelluric detection, characterized in that: Applied to a magnetotelluric sounding system, the device comprises: A data decoding module is used to decode and process the raw data of magnetotelluric sounding; wherein the decoded raw data includes: electric field data and magnetic field data; A data noise reduction module is configured to perform noise reduction processing on the decoded raw data; wherein the noise reduction processing includes: filtering out power frequency interference, eliminating DC components, removing low-frequency trend interference, and subtracting the amplitude, phase, and frequency response of the device; wherein the power frequency interference is filtered out from the decoded raw data to obtain first intermediate data; the DC component is eliminated from the first intermediate data to obtain second intermediate data; and the data samples in the second intermediate data are cumulatively moved and averaged to obtain the low-frequency trend interference; The data noise reduction module is used to perform noise reduction processing on the decoded original data, further comprising: eliminating the low-frequency trend interference from the second intermediate data to obtain third intermediate data; performing Fourier transform on the third intermediate data to obtain the third intermediate data in the frequency domain; and subtracting the device influence from the third intermediate data in the frequency domain to obtain the original data after noise reduction; wherein the device influence includes at least one of the following: the influence of the electromagnetic sensor, the amplitude influence of the receiver channel, and the influence of the phase frequency response; wherein the low-frequency trend interference is constrained by the following formula: Wherein, f(j) is the low-frequency trend interference, N1 is the length of the second intermediate data, N t is the length of the first intermediate data; An impedance determination module is used to perform impedance estimation on the raw data after normalization processing, and determine parameters corresponding to the raw data of the magnetotelluric sounding; wherein the parameters include at least one of the following: impedance tensor, apparent resistivity, impedance phase and dipole information.

7. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement the method for suppressing interference in magnetotelluric detection according to any one of claims 1 to 5.

8. A storage medium, characterized in that: The storage medium stores computer-executable instructions. When the computer-executable instructions are called and executed by the processor, the computer-executable instructions prompt the processor to implement the method for suppressing interference in magnetotelluric detection according to any one of claims 1 to 5.

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