A target body coordinate estimation method based on three-dimensional scanning geological radar

Abstract

The application provides a target body coordinate estimation method based on three-dimensional scanning geological radar, which performs one-dimensional filtering on geological radar data, then obtains horizontal boundary angles and pitch boundary angles through signal maximum value constraint, and finally obtains three-dimensional boundary coordinates and center coordinates of the underground target body through three-dimensional space coordinate conversion. The target body coordinate estimation method based on three-dimensional scanning geological radar can accurately obtain three-dimensional boundary coordinates and center coordinates of the underground target body, and is beneficial to three-dimensional space target body imaging and interpretation.

Description

Technical Field

[0001] This invention belongs to the field of geophysical exploration, specifically a target coordinate estimation method based on three-dimensional scanning ground-penetrating radar. This method is based on three-dimensional advanced detection ground-penetrating radar data and estimates the spatial coordinates of the corresponding underground target based on the spherical distribution characteristics of the ground-penetrating radar detection area 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 radar antenna to conduct three-dimensional spatial detection in front of the working face. The survey line has an arc shape in three-dimensional space, with the antenna position as the center. Therefore, the GPR detection area should exhibit a spherical distribution characteristic. This invention provides a target coordinate estimation method based on three-dimensional scanning GPR, which can estimate the spatial three-dimensional coordinates of corresponding underground targets, providing a clearer and more accurate description of the target range and distribution characteristics within the detection area. Summary of the Invention

[0005] The purpose of this invention is to estimate the spatial coordinates of the corresponding underground target based on the three-dimensional advanced detection ground-penetrating radar data and the spherical distribution characteristics of the ground-penetrating radar detection area in three-dimensional space.

[0006] This method obtains the three-dimensional boundary coordinates and center coordinates of the underground target body according to the following steps:

[0007] Step (A1): Process the ground-penetrating radar data D(α) i ,β j ,k), where i=0,1,...,N-1;j=0,1,...,N-1;k=1,2,...,H,α i β is the horizontal angle. j Let α be the pitch angle, k be the sampling point number, and H be the total number of sampling points. First, one-dimensional filtering is performed for a given horizontal angle α. i and pitch angle β j The following one-dimensional radar data D(α) i ,β j After filtering by the filtering function F(), we get k).

[0008] D f (α i ,β j ,k)=F(D(α i ,β j ,k))

[0009] Wherein, D(α) i ,β j The filtered data (k) is D. f (α i ,β j ,k);

[0010] Step (A2): For the filtered radar data D f (α i ,β j Let the sampling point number k = 1, and the maximum value of the signal is max(D). f (α i ,β j ,1)), solve

[0011]

[0012] Where λ is a constant, we obtain the corresponding i = U1, j = E1, where U1 ∈ {0, 1, ..., N-1}, E1 ∈ {0, 1, ..., N-1}, and the horizontal boundary angle is... and pitch boundary angle The horizontal and pitch boundary angles were calculated sequentially for different sampling point numbers to obtain... Step (A3): For Through three-dimensional spatial coordinate transformation, its three-dimensional coordinates can be represented as Where v is the average wave velocity of electromagnetic waves in the underground medium, and Δt is the detection time window corresponding to a unit sampling point;

[0013] Step (A4): Calculate sequentially The three-dimensional coordinates Connecting these H three-dimensional coordinates yields the three-dimensional boundary coordinates of the underground target.

[0014] Step (A5): Mean value of 3D boundary coordinates The coordinates are the center coordinates of the underground target.

[0015] The present invention has the following advantages:

[0016] 1. The target coordinate estimation method based on three-dimensional scanning ground-penetrating radar proposed in this invention can accurately obtain the three-dimensional boundary coordinates and center coordinates of underground targets, which is beneficial for target imaging and interpretation in three-dimensional space. Attached Figure Description

[0017] Figure 1 Flowchart of the technical method of this invention

[0018] Figure 2 This invention provides three-dimensional spatial imaging of ground-penetrating radar data. Detailed Implementation

[0019] The purpose of this invention is to estimate the spatial coordinates of the corresponding underground target based on the three-dimensional advanced detection ground-penetrating radar data and the spherical distribution characteristics of the ground-penetrating radar detection area in three-dimensional space.

[0020] The present invention provides a target coordinate estimation method based on three-dimensional scanning ground-penetrating radar, which is divided into two cases. In the first case, after one-dimensional filtering, there is exactly one target in the detection area. The specific steps are as follows:

[0021] (1) For the filtered ground-penetrating radar data D f (α i ,β j Let the sampling point number k = 1, and the maximum value of the signal is max(D). f (α i ,β j ,1)), solve

[0022]

[0023] Where λ is a constant, we obtain the corresponding i = U1, j = E1, where U1 ∈ {0, 1, ..., N-1}, E1 ∈ {0, 1, ..., N-1}, and the horizontal boundary angle is... and pitch boundary angle The horizontal and pitch boundary angles were calculated sequentially for different sampling point numbers to obtain...

[0024] In the second scenario, after one-dimensional filtering, there are two or more targets in the detection area. The specific steps are as follows:

[0025] (1) For the filtered ground-penetrating radar data D f (α i ,β j Let the sampling point number k = 1, and the maximum value of the signal is max(D). f (α i ,β j ,1)), solve

[0026]

[0027] Where λ is a constant, we obtain the corresponding i = U1, j = E1, where U1 ∈ {0, 1, ..., N-1}, E1 ∈ {0, 1, ..., N-1}, and the horizontal boundary angle is... and pitch boundary angle The horizontal and pitch boundary angles were calculated sequentially for different sampling point numbers to obtain...

[0028] (2) Set the data within the horizontal and elevation boundary angle ranges from the previous step to 0 to obtain new radar data D′. f (α i ,β j Let the sampling point number k = 1, and the signal maximum value be max(D′). f (α i ,β j ,1)), solve

[0029]

[0030] Where λ is a constant, we obtain the corresponding i = U1′, j = E1′, where U1′∈{0,1,...,N-1}, E1′∈{0,1,...,N-1}, and the horizontal boundary angle is... and pitch boundary angle Calculate the horizontal and pitch boundary angles for different sampling point numbers in sequence.

[0031] (3) Check if there are any new targets in the detection area. If there are, repeat step (2) above. If not, perform three-dimensional spatial coordinate transformation.

Claims

1. A target coordinate estimation method based on three-dimensional scanning ground-penetrating radar. This method uses three-dimensional advanced detection ground-penetrating radar data as a basis and estimates the spatial coordinates of the corresponding underground target based on the spherical distribution characteristics of the ground-penetrating radar detection area in three-dimensional space. The specific steps are as follows: Step (A1): Process the ground-penetrating radar data D(α) i ,β j ,k), where j=0,1,...,N-1;k=1,2,...,H,α i β is the horizontal angle. j Let α be the pitch angle, k be the sampling point number, and H be the total number of sampling points. First, one-dimensional filtering is performed for a given horizontal angle α. i and pitch angle β j The following one-dimensional radar data D(α) i ,β j After filtering by the filtering function F(), we get k). D f (a i ,b j ,k)=F(D(α i ,b j ,k)) in, D(α i ,β j The filtered data (k) is D. f (α i ,β j ,k); Step (A2): For the filtered radar data D f (α i ,β j Let the sampling point number k = 1, and the maximum value of the signal is max(D). f (α i ,β j ,1)), solve Where λ is a constant, we obtain the corresponding i = U1, j = E1, where U1 ∈ {0, 1, ..., N-1}, E1 ∈ {0, 1, ..., N-1}, and the horizontal boundary angle is... and pitch boundary angle The horizontal and pitch boundary angles were calculated sequentially for different sampling point numbers to obtain... Step (A3): For Through three-dimensional spatial coordinate transformation, its three-dimensional coordinates can be represented as Where v is the average wave velocity of electromagnetic waves in the underground medium, and Δt is the detection time window corresponding to a unit sampling point; Step (A4): Calculate sequentially The three-dimensional coordinates Connecting these H three-dimensional coordinates yields the three-dimensional boundary coordinates of the underground target. Step (A5): Mean value of 3D boundary coordinates The coordinates are the center coordinates of the underground target.

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