• Title, Summary, Keyword: ground-penetrating radar

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Application of Ground Penetrating Radar for Estimation of Loose Layer (지반 이완구간 추정을 위한 지하투과레이더의 적용)

  • Hong, Won-Taek;Kang, Seonghun;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.31 no.11
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    • pp.41-48
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    • 2015
  • An investigation of a void and a loose layer of the ground is essential in order to prevent the losses of life and properties caused by subsidence and sinkage of the ground. Recently, studies on the ground penetrating radar survey have been actively conducted in order to estimate the void and the loose layer of the ground. However, an error can be committed by contrarily predicting a dense ground and a loose layer because the ground penetrating radar estimates an interface depth between geo-materials that have different electrical impedances. In this study, a loose ground depth is estimated using the characteristics of the reflected electromagnetic wave obtained from the ground penetrating radar survey. To gather the signals according to the loose ground depths, the ground penetrating radar survey is conducted on a field which underwent a huge ground settlement. In addition, the dynamic cone penetration test is performed to verify the result of the loose ground depth estimation from the ground penetrating radar survey. From the analysis of the reflection characteristics of the electromagnetic wave, a phase of an electromagnetic wave reflected from a denser soil layer is found to be identical with that of the first measured signal. On the other hand, a phase of an electromagnetic wave reflected from the loose soil layer is found to be opposed to that of the first detected signal. The comparison between the dynamic cone penetration index and electromagnetic signals by the ground penetrating radar shows that the estimated depth of the loose or dense layer is perfectly matched with a high reliability. The ground penetrating radar survey and the signal analysis performed in this study can be used not only for the survey of interface depth between the discontinuity layers but also for the estimation of the loose layer.

Laboratory Experiments of a Ground-Penetrating Radar for Detecting Subsurface Cavities in the Vicinity of a Buried Pipe (매설관 주변 지하 공동 탐지를 위한 지하 탐사 레이다의 모의실험)

  • Hyun, Seung-Yeup
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.2
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    • pp.131-137
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    • 2016
  • In this paper, a feasibility on a ground-penetrating radar for detecting subsurface cavities near buried pipes has been investigated. The experimental setup was implemented by employing an impulse ground-penetrating radar system, a xy Cartesian coordinate robot, an underground material filled tank, a metal pipe and a simulated cavity model. In particular, the simulated cavity model was constructed by packing Styrofoam chips and balls, which have both similar electrical properties to an air-filled cavity and a solid shape. Through typical three experiments, B-scan data of the radar have been acquired and displayed as 2-D gray-scale images. According to the comparison of B-scan images, we show that the subsurface cavities near the buried pipes can be detected by using the radar survey.

Exploration of Buried Facilities by GPR (Ground Penetrating Radar를 사용한 지하설비 탐사에 관한 연구)

  • Shon, Su-Goog;Jeon, K.S.
    • Proceedings of the KIEE Conference
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    • pp.30-33
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    • 2001
  • This paper discusses the system design of a synthetic aperture radar system based on a pulse-echo radar. The design consists of an ultra-wide bandwidth antenna, an amplitude modulation, timing stabilities, and high speed a/d conversions with an equivalent-time sampling. Experiment results show that GPR(Ground Penetrating Radar) can be used to explore buried electric facilities.

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Design of Decoupled PMC-backed Air Waveguide Antenna for Continuous Wave Ground Penetrating Radar (상호 결합을 최소화한 연속파(CW) Ground Penetrating Radar(GPR)용 공기 도파관 안테나 설계)

  • 제도흥;나정웅
    • Proceedings of the IEEK Conference
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    • pp.177-180
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    • 2001
  • A decoupled, wide-band, perfectly magnetically conductor(PMC)-backed air waveguide antenna is designed and constructed for the use of the continuous electromagnetic wave ground penetrating radar in the frequency range from 200MHz to 600MHz. Two planar dipoles are located inside air slab covered by PMC on the top side and separated by an air gap from the bottom ground interface. The coupling between the transmitting and the receiving dipoles is calculated by less than -60dB over the frequency from 200MHz to 600MHz.

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Numerical study of electromagnetic wave propagation characteristics in collapsed building for rescue radar applications

  • Kwon, Kyeol;Kim, Dong-Kyoo;Choi, Youngwoo;Cho, Jeahoon;Jung, Kyung-Young
    • ETRI Journal
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    • v.40 no.4
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    • pp.546-553
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    • 2018
  • Since the Gyeongju earthquakes in 2016, there have been increased research interests in the areas of seismic design, building collapse, and rescue radar applications in Korea. Ground penetrating radar (GPR) is a nondestructive electromagnetic method that is used for underground surveys. To properly design ground penetrating radar that detects buried victims precisely, it is important to study electromagnetic wave propagation channel characteristics in advance. This work presents an electromagnetic propagation environment analysis of a trapped victim for GPR applications. In this study, we develop a realistic collapse model composed of layered reinforced concrete and a victim positioned horizontally. In addition, the effects of rebars and the distance between the radar antenna and target are investigated. The numerical analysis presents the electromagnetic wave propagation characteristics, including amplitude loss and phase difference, in the 450-MHz and 1,500-MHz frequency band, and it shows the electric field distribution in the environment.

Characteristic Changes in Ground-Penetrating Radar Responses from Dielectric-Filled Nonmetallic Pipes Buried in Inhomogeneous Ground (비균일 지하에 묻혀있는 유전체 충진 비금속관에 의한 지표투과레이다 응답의 특성 변화)

  • Hyun, Seung-Yeup
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.5
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    • pp.399-406
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    • 2019
  • The variation of ground-penetrating radar(GPR) signal characteristics from dielectric-filled nonmetallic pipes buried in inhomogeneous ground are compared through a numerical simulation. The relative permittivity distribution of the ground is generated by using the continuous random media(CRM) technique. As a function of the relative permittivity of the material filling the nonmetallic pipe buried in the ground media, GPR signals are simulated by using the finite-difference time-domain(FDTD) method. We show that, unlike the case for homogeneous ground, the distortion characteristics of the reflected waves caused by the front convex surface and the rear concave surface of the pipe buried in inhomogeneous ground are different depending on the permittivity contrast between the inside and outside of the pipe.

Examination on the influence of Depth, Size and Interval of Rebar on the Signal of Ground Penetrating Radar (철근의 깊이, 굵기 및 간격이 GPR 신호에 미치는 영향 조사)

  • Kim, Young-Joo;Lee, Seung-Seok;Ahn, Bong-Young;Kim, Young-Gil
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.4 no.2
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    • pp.167-174
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    • 2000
  • Ground penetrating radar(GPR) was applied for measuring depths, sizes and intervals of rebars embedded in concrete. A concrete wall was constructed for this study and a sand pool and a concrete block were used for simulation. Result of this study shows that GPR can be used for measuring rebar depths and intervals, even though it is limitary, but that measuring sizes is almost impossible. Simulation with the sand pool was helpful for research on the versatile rebar arrays though signal was not clear as real concrete wall. A concrete block with many cylindrical holes for inserting different sized rebars could not be used for simulator due to many unknown reflective waves. Antenna orientation must be perpendicular to rebars for large reflection signal.

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Detecting buried human remains using near-surface geophysical instruments

  • Powell Kathryn
    • Geophysics and Geophysical Exploration
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    • v.7 no.1
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    • pp.88-92
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    • 2004
  • To improve the recovery rate of unlocated buried human remains in forensic investigations, there is scope to evaluate and develop techniques that are applicable to the Australian environment. I established controlled gravesites (comprising shallow buried kangaroos, pigs, and human cadavers) in South Australia, to allow the methodical testing of remote sensing equipment for the purpose of grave detection in forensic investigations. Eight-month-old pig graves are shown to provide more distinct identifying results using ground-penetrating radar when compared to four-year-old kangaroo graves. Two further aspects of this research are presented: information (obtained from a survey) relating to the police use of geophysical instruments for locating buried human remains, and the use of electrical resistivity for locating human remains buried in a coffin. The survey of Australian police jurisdictions, covering the period 1995-2000, showed that police searches for unlocated bodies have not successfully located human remains using any geophysical instruments (such as ground-penetrating radar, magnetometers, or electrical resistivity). Lower resistivity readings were found coincident with the 150-year-old single historical burial in a heavily excavated field, in a situation where its exact location was previously unknown.

Antipersonnel Landmine Detection Using Ground Penetrating Radar

  • Shrestha, Shanker-Man;Arai, Ikuo;Tomizawa, Yoshiyuki;Gotoh, Shinji
    • Proceedings of the KSRS Conference
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    • pp.1064-1066
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    • 2003
  • In this paper, ground penetrating radar (GPR), which has the capability to detect non metal and plastic mines, is proposed to detect and discriminate antipersonnel (AP) landmines. The time domain GPR - Impulse radar and frequency domain GPR - SFCW (Stepped Frequency Continuous Wave) radar is utilized for metal and non-metal landmine detection and its performance is investigated. Since signal processing is vital for target reorganization and clutter rejection, we implemented the MUSIC (Multiple Signal Classification) algorithm for the signal processing of SFCW radar data and SAR (Synthetic Aperture Radar) processing method for the signal processing of Impulse radar data.

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Ground Penetrating Radar System for Landmine Detection Using 48 Channel UWB Impulse Radar (지뢰탐지용 48채널 배열 UWB 임펄스 레이더 방식 지면투과레이더시스템 개발)

  • Kwon, Ji-Hoon;Kwak, No-Jun;Ha, Seoung-Jae;Han, Seung-Hoon;Yoon, Yeo-Sun;Yang, DongWon
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.12
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    • pp.3-12
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    • 2016
  • This paper describes the development of the ground penetrating radar (GPR) system using UWB impulse radar with 48 Channel array. GPR is an effective alternative technology to resolve th disadvantages of metal detectors. Metal detectors have a very low detection probability of non-metallic landmine and high false alarm rates caused by metallic materials under the ground. In this paper, we use the mono-cycle pulse waveform with about 600 ps pulse width to obtain high resolution landmine microwave images. In order to analyze performances of this system, we utilize indoor test facility that made up of rough sandy loam which representative Korean soil. The mimic landmine models of metal/non-metal and anti-tank/anti-personnel landmines buried in DMZ (demilitarized zone) of Korea are used to analyze the detection depth and the shape of the mines using microwave image.