Research Paper

Split Viewer

Econ. Environ. Geol. 2024; 57(1): 17-23

Published online February 29, 2024

https://doi.org/10.9719/EEG.2024.57.1.17

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Characteristics of Ground-Penetrating Radar (GPR) Radargrams with Variable Antenna Orientation

Yoon Hyung Lee1, Seung-Sep Kim1,2,*

1Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon 34134, Korea
2Department of Geological Sciences, Chungnam National University, Daejeon 34134, Korea

Correspondence to : *seungsep@cnu.ac.kr

Received: January 16, 2024; Revised: January 23, 2024; Accepted: January 24, 2024

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.

Abstract

Ground penetrating radar (GPR) survey is a geophysical method that utilizes electromagnetic waves reflecting from a boundary where the electromagnetic property changes. As the frequency of the antenna is about 25 MHz ~ 1 GHz, it is effective to acquire high resolution images of underground pipe, artificial structure, underground cavity, and underground structure. In this study, we analyzed the change of signals reflected from the same underground objects according to the arrangement of transceiver antennas used in ground penetrating radar survey. The antenna used in the experiment was 200 MHz, and the survey was performed in the vertical direction across the sewer and the parallel direction along the sewer to the sewer buried under the road, respectively. A total of five antenna array methods were applied to the survey. The most used arrangement is when the transmitting and receiving antennas are all perpendicular to the survey line (PR-BD). The PR-BD arrangement is effective when the object underground is a horizontal reflector with an angle of less than 30°, such as the sewer under investigation. In this case study, it was confirmed that the transmitter and receiver antennas perpendicular to the survey line (PR-BD) are the most effective way to show the underground structure. In addition, in the case where the transmitting and receiving antennas are orthogonal to each other (XPOL), no specific reflected wave was observed in both experiments measured across or parallel to the sewer. Therefore, in the case of detecting undiscovered objects in the underground, the PR-BD array method in which the transmitting and receiving antennas are aligned in the direction perpendicular to the survey line taken as a reference and the XPOL method in which the transmitting and receiving antennas are orthogonal to each other are all used, it can be effective to apply both of the above arrangements after setting the direction to 45° and 135°.

Keywords ground-penetrating radar, antenna arrays, underground imaging

Article

Research Paper

Econ. Environ. Geol. 2024; 57(1): 17-23

Published online February 29, 2024 https://doi.org/10.9719/EEG.2024.57.1.17

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Characteristics of Ground-Penetrating Radar (GPR) Radargrams with Variable Antenna Orientation

Yoon Hyung Lee1, Seung-Sep Kim1,2,*

1Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon 34134, Korea
2Department of Geological Sciences, Chungnam National University, Daejeon 34134, Korea

Correspondence to:*seungsep@cnu.ac.kr

Received: January 16, 2024; Revised: January 23, 2024; Accepted: January 24, 2024

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.

Abstract

Ground penetrating radar (GPR) survey is a geophysical method that utilizes electromagnetic waves reflecting from a boundary where the electromagnetic property changes. As the frequency of the antenna is about 25 MHz ~ 1 GHz, it is effective to acquire high resolution images of underground pipe, artificial structure, underground cavity, and underground structure. In this study, we analyzed the change of signals reflected from the same underground objects according to the arrangement of transceiver antennas used in ground penetrating radar survey. The antenna used in the experiment was 200 MHz, and the survey was performed in the vertical direction across the sewer and the parallel direction along the sewer to the sewer buried under the road, respectively. A total of five antenna array methods were applied to the survey. The most used arrangement is when the transmitting and receiving antennas are all perpendicular to the survey line (PR-BD). The PR-BD arrangement is effective when the object underground is a horizontal reflector with an angle of less than 30°, such as the sewer under investigation. In this case study, it was confirmed that the transmitter and receiver antennas perpendicular to the survey line (PR-BD) are the most effective way to show the underground structure. In addition, in the case where the transmitting and receiving antennas are orthogonal to each other (XPOL), no specific reflected wave was observed in both experiments measured across or parallel to the sewer. Therefore, in the case of detecting undiscovered objects in the underground, the PR-BD array method in which the transmitting and receiving antennas are aligned in the direction perpendicular to the survey line taken as a reference and the XPOL method in which the transmitting and receiving antennas are orthogonal to each other are all used, it can be effective to apply both of the above arrangements after setting the direction to 45° and 135°.

Keywords ground-penetrating radar, antenna arrays, underground imaging

    Fig 1.

    Figure 1.Typical GPR antenna configurations (Allred, 2013). (a) Both perpendicular to the survey line (perpendicular-broadside, PRBD), (b) both parallel to the survey line (parallel-broadside, PL-BD), (c) serially perpendicular to the survey line (parallel-endfire, PL-EF), (d) serially parallel to the survey line (perpendicular-endfire, PR-EF), and (e) intersecting each other at the right angle (cross polarization, XPOL).
    Economic and Environmental Geology 2024; 57: 17-23https://doi.org/10.9719/EEG.2024.57.1.17

    Fig 2.

    Figure 2.Test survey site located at Chungnam National University, Daejeon, Korea: (a) Road view, (b) Schematic diagram of the survey lines.
    Economic and Environmental Geology 2024; 57: 17-23https://doi.org/10.9719/EEG.2024.57.1.17

    Fig 3.

    Figure 3.Processed radargram acquired along the perpendicular line to the underground pipe.
    Economic and Environmental Geology 2024; 57: 17-23https://doi.org/10.9719/EEG.2024.57.1.17

    Fig 4.

    Figure 4.Processed radargram acquired along the parallel line to the underground pipe.
    Economic and Environmental Geology 2024; 57: 17-23https://doi.org/10.9719/EEG.2024.57.1.17

    Fig 5.

    Figure 5.Simulated radargram. (a) Circular and rectangular bodies for simulation. (b) Simulated radargrams using gprMax2D (Giannopoulos, 2005).
    Economic and Environmental Geology 2024; 57: 17-23https://doi.org/10.9719/EEG.2024.57.1.17

    Fig 6.

    Figure 6.Survey configuration of XPOL at the incident angles of 45° and 135°.
    Economic and Environmental Geology 2024; 57: 17-23https://doi.org/10.9719/EEG.2024.57.1.17

    Fig 7.

    Figure 7.Radargrams acquired using XPOL configuration with (a) 45° and (b) 135° angles with respect to the buried pipe.
    Economic and Environmental Geology 2024; 57: 17-23https://doi.org/10.9719/EEG.2024.57.1.17
    KSEEG
    Apr 30, 2024 Vol.57 No.2, pp. 107~280

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