Results 101 to 110 of about 145 (123)
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The detection of cracks in blast-holes using directional borehole radar
2016 16th International Conference on Ground Penetrating Radar (GPR), 2016The detection of subsurface cracks and moisture in blast-holes is an important problem to be solved in open-cut coal mining. During the overburden removal process at open-cut coal mines, blast-holes are drilled and filled with ANFO explosive. Any explosive that extends into surrounding cracks within the blast-hole has the potential to remain unexploded
A. D. Strange, Z. Jecny
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$\hbox{HE}_{11}$ Mode Effect on Direct Wave in Single-Hole Borehole Radar
IEEE Transactions on Geoscience and Remote Sensing, 2011In this paper, we investigate the influence of radar sonde eccentricity on a direct wave between a transmitting and a receiving antenna in a single-hole borehole radar measurement. We analyze the direct wave using an analytical method with the approximated solution of branch cut integrals and that of residues of poles.
Satoshi Ebihara +2 more
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High range resolution directional borehole radar for 3-D fracture delineation
2009 IEEE International Geoscience and Remote Sensing Symposium, 2009Directional borehole radar was developed for detection of three-dimensional (3-D) target localization in single-hole radar measurement. Phase differences among four dipole elements of receiving circular array uniquely determine an azimuth direction of a reflected wave. Receiving voltages of dipole elements are measured by optical electric field sensors
Motoyuki Sato, Takuya Takayama
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Directional Borehole Radar With Dipole Antenna Array Using Optical Modulators
IEEE Transactions on Geoscience and Remote Sensing, 2004In this paper, we describe a directional borehole radar comprising a dipole antenna array with an optical modulator capable of determining the position of targets in three dimensions (3-D). Optical modulators using a Mach-Zehnder interferometer are used to transform electrical signals into optical signals at the feeding points of the dipole antennas ...
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Probe rotation effects on direction of arrival estimation in array‐type directional borehole radar
Near Surface Geophysics, 2017ABSTRACTThis paper discusses the relationship between feeding line delay compensation and direction of arrival estimation in an array‐type directional borehole radar. In this radar, since the space available for an array antenna is limited by the borehole diameter, direction of arrival estimation is based on small travel time differences among array ...
Satoshi Ebihara +3 more
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Small-diameter directional borehole radar system with 3D sensing capability
Proceedings of the 15th International Conference on Ground Penetrating Radar, 2014This paper describes a new directional borehole radar system and its field testing. The system uses a thin radar probe (57 mm diameter) and a circular dipole array directive antenna. The radar is of the step frequency type with a network analyzer. Through careful antenna design, we were able to achieve the compact radar probe and precise measurement at
K Wada, S Karasawa, K Kawata, S Ebihara
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18th International Conference on Ground Penetrating Radar, Golden, Colorado, 14–19 June 2020, 2020
Satoshi Ebihara +5 more
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Satoshi Ebihara +5 more
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A directional antenna for borehole radar measurements
Geoexploration, 1989O. Olsson +4 more
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A directional borehole radar system for subsurface imaging
2002Electrical Engineering, Mathematics and Computer ...
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Proceedings of the 14th SEGJ International Symposium, Online, 18–21 October 2021, 2021
Yuki Tsujikawa +4 more
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Yuki Tsujikawa +4 more
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