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Proceedings Paper

"Broadside" versus "end-fire" radar response: some simple illustrative examples
Author(s): David C. Nobes; A. Peter Annan
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Paper Abstract

A few field studies have noted a directional dependence in the ground-penetrating radar response. Such observations are consistent with the character of the signal transmitted from a GPR antenna into the ground under different conditions. However, the antenna orientation relative to the target geometry is seldom given much consideration in GPR survey design and execution. We use simple models to illustrate the influence of antenna orientation relative to dipping reflectors. The two fundamental responses are presented: The 'broadside' response arises when the transmitting and receiving antenna axes are parallel to the strike of the dipping feature. The 'end-fire' response is obtained when the antennas are perpendicular to the strike. Both the reflector dip and host velocity are varied. Antenna orientation relative to the target is important because of the lobate nature of the transmitted GPR signal. The signal strength is zero or almost zero at 'null points,' where the energy available for reflection is small, and any reflected energy is almost non- existent. The broadside and end-fire signals have different forms, and yield different responses to dipping features. Thus, if the angle at which a null occurs is complementary to the angle of the dip, then little or no reflection occurs.

Paper Details

Date Published: 27 April 2000
PDF: 6 pages
Proc. SPIE 4084, Eighth International Conference on Ground Penetrating Radar, (27 April 2000); doi: 10.1117/12.383501
Show Author Affiliations
David C. Nobes, Univ. of Canterbury (New Zealand)
A. Peter Annan, Sensors & Software, Inc. (Canada)

Published in SPIE Proceedings Vol. 4084:
Eighth International Conference on Ground Penetrating Radar
David A. Noon; Glen F. Stickley; Dennis Longstaff, Editor(s)

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