Call number:
ZSP-201-85/19
In:
CRREL Report, 85-19
Description / Table of Contents:
Ground-probing radar can be an effective tool for exploring the top 10 to 20 m of ground, especially in cold regions where the freezing of water decreases signal absorption. However, the large electrical variability of the surface, combined with the short wavelengths used, can often cause severe ground clutter that can mask a desired, deeper return. In this study a model facility was constructed consisting of a metallic reflector covered by sand. Troughs of saturated sand were emplaced at the surface to vary surface electrical properties and to act as a noise source to interfere with the bottom reflections. Antenna polarization and height, and signal stacking in both static (antennas stationary) and dynamic (antennas moving) modes were then investigated as methods for reducing the surface clutter. Polarization parallel to the profile direction (perpendicular to the troughs' axes) gave profiles superior to the perpendicular case because of the directional sensitivity of the antenna radiation. Dynamic stacking greatly improved the signal-to-noise ratio because noise sources were averaged as the antennas moved, while the desired reflector, buried at constant depth, was enhanced. Raising the antennas above the surface also reduced noise because the surface area over which reflections were integrated increased. All three noise reduction techniques could be effective in surveys for reflectors at nearly constant depth such as groundwater tables or ice/water interfaces if the lateral variation in undesired ground propertiesis sufficiently random.
Type of Medium:
Series available for loan
Pages:
iv, 23 Seiten
,
Illustrationen
Series Statement:
CRREL Report 85-19
URL:
https://apps.dtic.mil/dtic/tr/fulltext/u2/a163208.pdf
URL:
https://hdl.handle.net/11681/9440
Language:
English
Note:
CONTENTS
Abstract
Preface
Introduction
Objective and procedures
Materials and methods
Subsurface radar
Model facility
Results
Isolated disturbances-surface and raised analog profiles
Multiple disturbances
Discussion and conclusions
Literature cited
Location:
AWI Archive
Branch Library:
AWI Library
