Analysis of cross-borehole pulse radar signatures measured at various tunnel angles*

Sang-Wook Kim; Se-Yun Kim

doi:10.1071/EG09048

RESEARCH ARTICLE

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Analysis of cross-borehole pulse radar signatures measured at various tunnel angles^*

Sang-Wook Kim ¹ Se-Yun Kim ² ³

+ Author Affiliations

- Author Affiliations

¹ School of Electrical Engineering, Seoul National University, 599, Gwanangno, Gwanak-gu, Seoul 151-744, Korea.

² Imaging Media Research Centre, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791, Korea.

³ Corresponding author. Email: ksy@imrc.kist.re.kr

Exploration Geophysics 41(1) 96-101 https://doi.org/10.1071/EG09048
Submitted: 10 September 2009 Accepted: 18 November 2009 Published: 19 February 2010

Abstract

A pulse radar system has been developed recently to detect dormant underground tunnels that are deeply located at depths of hundreds of metres. To check the ability of the radar system to detect an obliquely oriented tunnel, five different borehole pairs in the tunnel test site were chosen so that the horizontal lines-of-sight cut the tunnel axis obliquely, in 15° steps. The pulse radar signatures were measured over a depth range of 20 m around the centre of the air-filled tunnel. Three canonical parameters, consisting of the arrival time, attenuation, and dispersion time were extracted from the first and second peaks of the measured radar signatures. Using those parameters, the radar system can detect obliquely oriented tunnels at various angles up to 45° from the transmitter-receiver line of sight.

Key words: cross-borehole radar, pulse radar, tunnel detection.

Acknowledgement

This research has been supported by the Intelligent Microsystem Center (IMC; http://www.microsystem.re.kr), which carries out one of the 21st century’s Frontier R & D Projects sponsored by the Korea Ministry of Knowledge and Economy.

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¹ ^*Part of this paper was presented at the 9th SEGJ International Symposium (2009).