A geological radar three-dimensional advanced detection data superposition method

Abstract

The application provides a geological radar three-dimensional advanced detection data stacking method, which corresponds original sampling point data and to-be-stacked sampling point data through air correction and three-dimensional space position estimation according to the spherical distribution characteristics of a geological radar detection region in a three-dimensional space, stacks geological radar data of different observation points in a unified coordinate system, obtains stacked sampling point data through frequency domain stacking, reduces multiple wave interference of the geological radar signal, and is beneficial to target positioning in the three-dimensional space.

Description

Technical Field

[0001] This invention belongs to the field of geophysical exploration, specifically a method for superimposing three-dimensional advanced detection data from ground-penetrating radar. Based on three-dimensional advanced detection ground-penetrating radar data, and according to the spherical distribution characteristics of the ground-penetrating radar detection area in three-dimensional space, the ground-penetrating radar data from different observation points are superimposed onto a unified coordinate system to achieve data superposition, reduce multiple wave interference of ground-penetrating radar signals, and facilitate target positioning in three-dimensional space. Background Technology

[0002] During coal mining, geological structural changes are easily triggered, and hidden geological anomalies (such as faults, collapse columns, and folds) can easily lead to mining accidents. Major mining accidents include roof collapse, coal and gas outbursts, and mine water inrush. Ground-penetrating radar (GPR), as an effective geophysical exploration tool, is suitable for detecting geological structural anomalies such as faults, collapse columns, and folds. Three-dimensional scanning GPR, by rotating the antenna angle, is used for three-dimensional spatial exploration in front of the working face, and can also be used for directional exploration of sidewalls, mining areas, etc., enabling rapid identification and three-dimensional imaging of geological structures.

[0003] Three-dimensional spatial scanning ground-penetrating radar transmits high-frequency broadband electromagnetic waves in pulse form to the working face. A portion of these waves travels directly from the transmitting antenna to the receiving antenna, forming a coupled wave. Another portion, after being transmitted, is reflected back from the air-surface interface without penetrating underground, forming a direct wave. Coupled waves and direct waves are often collectively referred to as direct-coupled waves, frequently used to determine the zero-time point as a reference for judging the depth of underground targets. The remaining electromagnetic waves propagate into the medium ahead of the working face. When they encounter targets with electrical differences (such as faults, collapse columns, folds, etc.) or interfaces between different media, the electromagnetic waves are reflected back to the working face and received by the receiving antenna. After acquisition, processing, and storage, the received signals become ground-penetrating radar data containing information about the medium ahead of the working face.

[0004] Three-dimensional spatial scanning ground-penetrating radar (GPR) uses the angle of the rotating GPR antenna to detect objects in three-dimensional space in front of the working face. The survey line is arc-shaped in three-dimensional space, with the antenna position as the center. Therefore, the GPR detection area exhibits a spherical distribution in three-dimensional space. This invention provides a method for superimposing GPR data from three-dimensional advanced detection, which allows GPR data from different observation points to be superimposed onto a unified coordinate system. This data superposition reduces multiple wave interference in the GPR signal, facilitating target localization in three-dimensional space. Summary of the Invention

[0005] The purpose of this invention is to match the original sampling point data with the sampling point data to be superimposed by air correction and three-dimensional spatial position estimation based on the characteristics of ground-penetrating radar data, and obtain the superimposed sampling point data by frequency domain superposition.

[0006] The specific steps of this method are as follows:

[0007] Step (A1): The ground-penetrating radar data to be overlaid are D1(α) i ,β j ,k),D2(α) i ,β j ,k), where α i β is the horizontal angle. j Let α be the pitch angle, N be the total number of angles, k be the sampling point number, and H be the total number of sampling points. First, air correction is performed to convert the corresponding mileage in the air to the mileage in the underground medium. For a given horizontal angle α... i and pitch angle β j The following one-dimensional radar data D1(α) i ,β j After correction by the air correction function G(), we get k).

[0008]

[0009] Wherein, D1(α) i ,β j The corrected data is (k) D2(α i ,β j The corrected data is (k)

[0010] Step (A2): For the corrected radar data Let the original sampling point data be... The following method obtains the data of the sampling points to be superimposed at the corresponding locations through three-dimensional spatial location estimation. U1, V1, and K1 are known to be the data... The horizontal angle, elevation angle, and sampling point number are given, v is the average electromagnetic wave velocity in the underground medium, and Δt is the detection time window corresponding to each sampling point. Let the horizontal spacing between observation points be d and the elevation spacing be h. The mileage in the air is corrected to the mileage in the underground medium as follows: Data of sampling points to be superimposed The corresponding horizontal angle U2, pitch angle V2, and sampling point number K2 are as follows:

[0011]

[0012]

[0013]

[0014] Step (A3): For the sampling point data... and Frequency domain superposition, Overlay The result after superposition is:

[0015]

[0016] Among them, F() and F -1 () represent the frequency domain transform function and the inverse transform function, respectively. This is the superimposed sampling point data.

[0017] The present invention has the following advantages:

[0018] 1. The air correction function proposed in this invention can convert the corresponding mileage in the air into the mileage in the underground medium, thereby improving the accuracy of target positioning in three-dimensional space.

[0019] 2. The three-dimensional spatial location estimation method proposed in this invention can obtain the sampling point data to be superimposed at the corresponding location, creating conditions for the superposition of geological radar data from different observation points. Attached Figure Description

[0020] Figure 1 Flowchart of the technical method of this invention

[0021] Figure 2 Comparison of ground-penetrating radar data before and after overlay in this invention Detailed Implementation

[0022] This invention addresses the characteristics of three-dimensional spatial scanning ground-penetrating radar antenna rotation acquisition data. Through air correction and three-dimensional spatial position estimation, it correlates the original sampling point data with the sampling point data to be superimposed. By superimposing in the frequency domain, the superimposed sampling point data is obtained, which can reduce the interference of multiple waves in the ground-penetrating radar signal and is beneficial for target positioning in three-dimensional space.

[0023] The present invention provides a method for overlaying three-dimensional advanced detection data from ground-penetrating radar, which requires that the observation points lie in the same plane and that the plane is perpendicular to the detection direction. The specific steps are as follows:

[0024] (1) The ground-penetrating radar data to be overlaid are D1(α) i ,β j ,k),D2(α) i ,β j ,k), where α i β is the horizontal angle. jLet α be the pitch angle, N be the total number of angles, k be the sampling point number, and H be the total number of sampling points. First, air correction is performed to convert the corresponding mileage in the air to the mileage in the underground medium. For a given horizontal angle α... i and pitch angle β j The following one-dimensional radar data D1(α) i ,β j After correction by the air correction function G(), we get k).

[0025]

[0026] Wherein, D1(α) i ,β j The corrected data is (k) D2(α i ,β j The corrected data is (k)

[0027] (2) For the corrected radar data Let the original sampling point data be... The following method obtains the data of the sampling points to be superimposed at the corresponding locations through three-dimensional spatial location estimation. U1, V1, and K1 are known to be the data... The horizontal angle, elevation angle, and sampling point number are given, v is the average electromagnetic wave velocity in the underground medium, and Δt is the detection time window corresponding to each sampling point. Let the horizontal spacing between observation points be d and the elevation spacing be h. The mileage in the air is corrected to the mileage in the underground medium as follows: Data of sampling points to be superimposed The corresponding horizontal angle U2, pitch angle V2, and sampling point number K2 are as follows:

[0028]

[0029]

[0030]

[0031] (3) For the sampling point data and Frequency domain superposition, Overlay The result after superposition is:

[0032]

[0033] Among them, F() and F -1 () represent the frequency domain transform function and the inverse transform function, respectively. This is the superimposed sampling point data.

Claims

1. A method for overlaying three-dimensional advanced detection data from ground-penetrating radar (GPR), which uses three-dimensional advanced detection GPR data as a basis and, based on the spherical distribution characteristics of the GPR detection area in three-dimensional space, overlays GPR data from different observation points onto a unified coordinate system to achieve data overlay. The specific steps are as follows: Step (A1): The ground-penetrating radar data to be overlaid are D1(α) i ,β j ,k),D2(α) i ,β j ,k), where α i β is the horizontal angle. j Let α be the pitch angle, N be the total number of angles, k be the sampling point number, and H be the total number of sampling points. First, air correction is performed to convert the corresponding mileage in the air to the mileage in the underground medium. For a given horizontal angle α... i and pitch angle β j The following one-dimensional radar data D1(α) i ,β j After correction by the air correction function G(), we get: in, D1(α i ,β j The corrected data is (k) D2(α i ,β j The corrected data is (k) Step (A2): For the corrected radar data Let the original sampling point data be The following method obtains the data of the sampling points to be superimposed at the corresponding locations through three-dimensional spatial location estimation. U1, V1, and K1 are known to be the data... The horizontal angle, elevation angle, and sampling point number are given, v is the average electromagnetic wave velocity in the underground medium, and Δt is the detection time window corresponding to each sampling point. Let the horizontal spacing between observation points be d and the elevation spacing be h. The mileage in the air is corrected to the mileage in the underground medium as follows: Data of sampling points to be superimposed The corresponding horizontal angle U2, pitch angle V2, and sampling point number K2 are as follows: Step (A3): For the sampling point data... and Frequency domain superposition, Overlay The result after superposition is: Among them, F() and F -1 () represent the frequency domain transform function and the inverse transform function, respectively. This is the superimposed sampling point data.

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