Magnetic three-component data extraction method in aviation transient electromagnetic-magnetic method combined detection system

Abstract

A method for extracting magnetic three-component data in an aviation transient electromagnetic-magnetic method combined detection system belongs to the technical field of aviation transient electromagnetic exploration, and comprises the following steps: a data acquisition module acquires original magnetic three-component data of a target detection area, and then the original magnetic three-component data is processed by a preprocessing module to obtain standard magnetic three-component data; the magnetic field calculation filtering module calculates an original magnetic total field value according to the standard magnetic three-component data, and then obtains a magnetic field value caused by a transient electromagnetic primary field through sliding filtering processing; the image drawing module draws a curve graph according to the magnetic field value; a sample extraction module extracts sample data from the curve graph; and the cyclic calculation module performs cyclic calculation on periodic data of the curve graph according to the curve graph and the sample data, and finally calculates magnetic three-component data without transient electromagnetic interference. The method has the effect that pure geomagnetic data which is not interfered by transient electromagnetic interference can be accurately and effectively extracted from original magnetic three-component data.

Description

Technical Field

[0001] This invention relates to the field of airborne transient electromagnetic exploration technology, and in particular to a method for extracting magnetic three-component data in an airborne transient electromagnetic-magnetic joint detection system. Background Technology

[0002] The airborne transient electromagnetic-magnetic joint detection system can simultaneously acquire both transient electromagnetic and magnetic data in a single flight mission, greatly improving work efficiency. Furthermore, the combined interpretation of the two methods reduces ambiguity and enhances exploration accuracy. During data acquisition, the three-component fluxgate probe operates in continuous sampling mode. The acquired data includes not only information on the geomagnetic field and magnetic anomalies but also information on the primary and secondary transient electromagnetic fields. Therefore, it is necessary to extract the portion of the raw magnetic three-component data that is unaffected by transient electromagnetic interference for subsequent processing and interpretation.

[0003] The drawback of existing technologies is that existing magnetic three-component data extraction methods cannot accurately and effectively extract pure geomagnetic data that is not affected by transient electromagnetic interference from the original magnetic three-component data. Summary of the Invention

[0004] The present invention provides a method for extracting magnetic three-component data in an airborne transient electromagnetic-magnetic joint detection system, which can accurately and effectively extract pure geomagnetic data unaffected by transient electromagnetic interference from the original magnetic three-component data.

[0005] To achieve the above objectives, this invention provides a method for extracting magnetic three-component data in an airborne transient electromagnetic-magnetic joint detection system. The key features include the following steps:

[0006] Step 1: Construct a magnetic three-component data extraction system, which is equipped with a data acquisition module, a preprocessing module, a magnetic field calculation and filtering module, an image rendering module, a sample extraction module, and a loop calculation module connected in sequence.

[0007] Step 2: The data acquisition module acquires the raw magnetic three-component data of the target detection area. This raw magnetic three-component data is then processed by the preprocessing module to obtain standard magnetic three-component data. ;

[0008] Step 3: The magnetic field calculation and filtering module calculates and filters the standard magnetic three-component data. The original total magnetic field value was calculated. Then, the original total magnetic field value is adjusted using a sliding window. A sliding filter is performed to obtain the magnetic field value caused by the transient electromagnetic primary field. ;

[0009] Step 4: The image drawing module calculates the magnetic field value. , drawing A graph, and then from the above The excitation period length of the transient electromagnetic primary field is obtained from the curve. and positive excitation delay length and according to and The negative excitation delay length was calculated. ;

[0010] Step 5: The sample extraction module extracts samples from the... A positive excitation start point is randomly selected from the curve graph as the sample starting point, and the excitation period length is used as the starting point. The sample length is used for sample extraction to obtain sample data. ;

[0011] Step 6: The loop calculation module calculates according to the... Curve graphs and sample data Regarding the above The periodic data of the curve are cyclically calculated to finally obtain the magnetic three-component data that does not contain transient electromagnetic interference.

[0012] Through the above design, this invention performs a series of processes on the original magnetic three-component data, including preprocessing, calculation filtering, and image rendering, and then extracts and combines the resulting sample data. The periodic data from the curve is used to iteratively calculate and obtain pure geomagnetic data, which is free from transient electromagnetic interference. This method is simple to operate and can quickly, accurately, and effectively extract pure geomagnetic data unaffected by transient electromagnetic interference from the original magnetic three-component data.

[0013] The extracted magnetic three-component data, which does not contain transient electromagnetic interference, i.e., pure geomagnetic data, can be used for ore body detection and analysis in the target detection area, facilitating mineral resource identification and subsequent mineral development.

[0014] Preferably, in step 2, the data acquisition module is a drone equipped with a magnetic probe, which is used to collect and store the original magnetic three-component data of the target detection area.

[0015] The UAV is equipped with a magnetic probe to collect and store the raw three-component magnetic data of the target detection area, and then exports the collected raw three-component magnetic data to the host computer for further processing.

[0016] Preferably, in step 2, the preprocessing module removes null values ​​and extreme outliers from the original magnetic tri-component data to obtain standard magnetic tri-component data. .

[0017] This invention effectively improves data quality by performing preprocessing operations such as removing null values ​​and extreme outliers from the original magnetic three-component data, providing stable and high-quality input data for subsequent processing.

[0018] Preferably, in step 3, the magnetic field calculation and filtering module calculates the original total magnetic field value. The expression is:

[0019] ;

[0020] in, This represents the original total magnetic field value. This is the magnetic component data in the x-direction. This is the magnetic component data in the y-direction. This is the magnetic component data in the z-direction.

[0021] The specific filtering method of the magnetic field calculation and filtering module is as follows: set a sliding window n, call the library function to calculate the sliding median mT of the original total magnetic field value T, and subtract mT from T to obtain the magnetic field value peT caused by the transient electromagnetic primary field.

[0022] Preferably: in step 4, the The curve graph contains at least two complete transient electromagnetic primary field excitation cycles;

[0023] The image rendering module according to and Calculate the negative excitation delay length The expression is:

[0024] .

[0025] Preferably, in step 6, the loop calculation module obtains magnetic three-component data that does not contain transient electromagnetic interference through loop calculation. The specific process is as follows:

[0026] Step 6.1: The loop calculation module starts from the... The first curve in the graph Starting from a point, based on the excitation cycle length Extract the data segment and calculate the data segment With the sample data The correlation value is calculated and recorded in the correlation value sequence. middle; , , Indicates the magnetic field value Length, Representing sample data The length.

[0027] Step 6.2: The loop calculation module calculates the correlation value sequence based on the set similarity value S. In the sequence, find the locations of data points with a similarity greater than S and record them in the array. middle;

[0028] Step 6.3: The loop calculation module calculates the sequence. First derivative sequence Then, in the sequence of first derivatives Find the data point with a value greater than 1 in the sequence, and add 1 to the index of that position and record it in the sequence. middle;

[0029] Step 6.4: The loop calculation module uses a sequence of numbers. The position number is in the sequence. The corresponding data values ​​are selected from the data, and these data values ​​are compared with the positive excitation delay length. Negative excitation delay length Add them separately and record them in a sequence. and middle, This is the delayed value point of the transient electromagnetic positive excitation. This is the delayed value point of the transient electromagnetic negative excitation.

[0030] Step 6.5: The loop calculation module calculates from the sequence... and The Starting from a point, respectively in the standard magnetic three components Extract the data values ​​corresponding to the delayed values ​​of transient electromagnetic positive excitation and transient electromagnetic negative excitation, and record the average of the sum of the two values ​​in a sequence. In the sequence The data in the data set is the magnetic three-component data excluding transient electromagnetic interference. Among them, , , Representing a sequence The length.

[0031] As a priority: In step 6.1, the loop calculation module calculates the data segment. With the sample data The expression for the correlation value is:

[0032] ;

[0033] in, Describing covariance, Indicates variance.

[0034] The beneficial effects of the present invention are as follows: The present invention provides a method for extracting magnetic three-component data in an airborne transient electromagnetic-magnetic joint detection system. It is simple to operate and can quickly, accurately and effectively extract pure geomagnetic data from the original magnetic three-component data that is not affected by transient electromagnetic interference. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the process of the present invention;

[0036] Figure 2 As in the embodiments Line graph. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific examples. The following embodiments or drawings are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0038] like Figure 1 As shown, a method for extracting magnetic three-component data in an airborne transient electromagnetic-magnetic joint detection system includes the following steps:

[0039] Step 1: Construct a magnetic three-component data extraction system, which is equipped with a data acquisition module, a preprocessing module, a magnetic field calculation and filtering module, an image rendering module, a sample extraction module, and a loop calculation module connected in sequence.

[0040] Step 2: The data acquisition module acquires the raw magnetic three-component data of the target detection area. This raw magnetic three-component data is then processed by the preprocessing module to obtain standard magnetic three-component data. The preprocessing module processes the raw magnetic three-component data by removing null values ​​and extreme outliers.

[0041] Step 3: The magnetic field calculation and filtering module calculates and filters the standard magnetic three-component data. The original total magnetic field value was calculated. The expression is:

[0042] ;

[0043] in, This represents the original total magnetic field value. This is the magnetic component data in the x-direction. This is the magnetic component data in the y-direction. This is the magnetic component data in the z-direction.

[0044] Then, the original total magnetic field value is adjusted via a sliding window. A sliding filter is performed to obtain the magnetic field value caused by the transient electromagnetic primary field. ;

[0045] Step 4: The image drawing module calculates the magnetic field value. , drawing Line graph, such as Figure 2 As shown, then from the The excitation period length of the transient electromagnetic primary field is obtained from the curve. and positive excitation delay length and according to and The negative excitation delay length was calculated. The expression is: .

[0046] The The curve contains at least two complete transient electromagnetic primary field excitation cycles.

[0047] Excitation cycle length The data length between two positive trigger jump points, for example Figure 2 In the middle: the period length = 199 - 33 + 1 = 167.

[0048] Positive excitation delay length The data length delayed from the positive excitation start point needs to ensure that the delayed value point is in a smooth region between the positive and negative excitations, for example... Figure 2 In the middle: the value of the positive excitation delay length is set at 70, which meets the requirements, so the delay length is 70-33+1=38.

[0049] Step 5: The sample extraction module extracts samples from the... A positive excitation start point is randomly selected from the curve graph as the sample starting point, and the excitation period length is used as the starting point. The sample length is used for sample extraction to obtain sample data. ;

[0050] Step 6: The loop calculation module starts from the... The first curve in the graph Starting from a point, based on the excitation cycle length Extract the data segment and calculate the data segment With the sample data The correlation value is calculated and recorded in the correlation value sequence. The correlation value calculation expression is as follows:

[0051] ;

[0052] in, Describing covariance, Indicates variance.

[0053] The cyclic calculation module calculates the correlation value sequence based on a set similarity value S. In the sequence, find the locations of data points with a similarity greater than S and record them in the array. middle;

[0054] The loop calculation module calculates the sequence. First derivative sequence Then, in the sequence of first derivatives Find the data point with a value greater than 1 in the sequence, and add 1 to the index of that position and record it in the sequence. middle;

[0055] The loop calculation module uses a sequence The position number is in the sequence. The corresponding data values ​​are selected from the data, and these data values ​​are compared with the positive excitation delay length. Negative excitation delay length Add them separately and record them in a sequence. and middle, This is the delayed value point of the transient electromagnetic positive excitation. This is the delayed value point of the transient electromagnetic negative excitation.

[0056] The loop calculation module calculates from the sequence and The Starting from a point, respectively in the standard magnetic three components Extract the data values ​​corresponding to the delayed values ​​of transient electromagnetic positive excitation and transient electromagnetic negative excitation, and record the average of the sum of the two values ​​in a sequence. In the sequence The data in the data is the magnetic three-component data that does not contain transient electromagnetic interference.

[0057] The extracted magnetic three-component data, which does not contain transient electromagnetic interference, i.e., pure geomagnetic data, can be used for ore body detection and analysis in the target detection area, facilitating mineral resource identification and subsequent mineral development.

[0058] The data acquisition module is a drone equipped with a magnetic probe, which is used to collect and store the raw magnetic three-component data of the target detection area.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for extracting magnetic three-component data in an airborne transient electromagnetic-magnetic joint detection system, characterized in that, Includes the following steps: Step 1: Construct a magnetic three-component data extraction system, which is equipped with a data acquisition module, a preprocessing module, a magnetic field calculation and filtering module, an image rendering module, a sample extraction module, and a loop calculation module connected in sequence. Step 2: The data acquisition module acquires the raw magnetic three-component data of the target detection area. This raw magnetic three-component data is then processed by the preprocessing module to obtain standard magnetic three-component data. ; Step 3: The magnetic field calculation and filtering module calculates and filters the standard magnetic three-component data. The original total magnetic field value was calculated. Then, the original total magnetic field value is adjusted using a sliding window. A sliding filter is performed to obtain the magnetic field value caused by the transient electromagnetic primary field. ; Step 4: The image drawing module calculates the magnetic field value. , drawing A graph, and then from the above The excitation period length of the transient electromagnetic primary field is obtained from the curve. and positive excitation delay length and according to and The negative excitation delay length was calculated. ; Step 5: The sample extraction module extracts samples from the... A positive excitation start point is randomly selected from the curve graph as the sample starting point, and the excitation period length is used as the starting point. The sample length is used for sample extraction to obtain sample data. ; Step 6: The loop calculation module calculates according to the... Curve graphs and sample data Regarding the above The periodic data of the curve are cyclically calculated to finally obtain the magnetic three-component data that does not contain transient electromagnetic interference.

2. The method for extracting magnetic three-component data in the airborne transient electromagnetic-magnetic joint detection system according to claim 1, characterized in that: In step 2, the data acquisition module is a drone equipped with a magnetic probe, which is used to collect and store the raw magnetic three-component data of the target detection area.

3. The method for extracting magnetic three-component data in the airborne transient electromagnetic-magnetic joint detection system according to claim 1, characterized in that: In step 2, the preprocessing module removes null values ​​and extreme outliers from the original magnetic tri-component data to obtain standard magnetic tri-component data. .

4. The method for extracting magnetic three-component data in the airborne transient electromagnetic-magnetic joint detection system according to claim 1, characterized in that: In step 3, the magnetic field calculation and filtering module calculates the original total magnetic field value. The expression is: ； in, This represents the original total magnetic field value. This is the magnetic component data in the x-direction. This is the magnetic component data in the y-direction. This is the magnetic component data in the z-direction.

5. The method for extracting magnetic three-component data in the airborne transient electromagnetic-magnetic joint detection system according to claim 1, characterized in that: In step 4, the The curve graph contains at least two complete transient electromagnetic primary field excitation cycles; The image rendering module according to and Calculate the negative excitation delay length The expression is: 。 6. The method for extracting magnetic three-component data in the airborne transient electromagnetic-magnetic joint detection system according to claim 1, characterized in that: In step 6, the loop calculation module obtains magnetic three-component data that does not contain transient electromagnetic interference through loop calculation. The specific process is as follows: Step 6.1: The loop calculation module starts from the... The first curve in the graph Starting from a point, to the length of the excitation cycle Extract the data segment and calculate the data segment With the sample data The correlation value is calculated and recorded in the correlation value sequence. middle; Step 6.2: The loop calculation module calculates the correlation value sequence based on the set similarity value S. In the sequence, find the locations of data points with a similarity greater than S and record them in the array. middle; Step 6.3: The loop calculation module calculates the sequence. First derivative sequence Then, in the sequence of first derivatives Find the data point with a value greater than 1 in the sequence, and add 1 to the index of that position and record it in the sequence. middle; Step 6.4: The loop calculation module uses a sequence of numbers. The position number is in the sequence. The corresponding data values ​​are selected from the data, and these data values ​​are compared with the positive excitation delay length. Negative excitation delay length Add them separately and record them in a sequence. and middle, This is the delayed value point of the transient electromagnetic positive excitation. This is the delayed value point of the transient electromagnetic negative excitation. Step 6.5: The loop calculation module calculates from the sequence... and The Starting from a point, respectively in the standard magnetic three components Extract the data values ​​corresponding to the delayed values ​​of transient electromagnetic positive excitation and transient electromagnetic negative excitation, and record the average of the sum of the two values ​​in a sequence. In the sequence The data in the data is the magnetic three-component data that does not contain transient electromagnetic interference.

7. The method for extracting magnetic three-component data in the airborne transient electromagnetic-magnetic joint detection system according to claim 6, characterized in that: In step 6.1, the loop calculation module calculates the data segment. With the sample data The expression for the correlation value is: ； in, Describing covariance, Indicates variance.

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