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Proceedings Paper

Advanced array techniques for unattended ground sensor applications
Author(s): Fred E. Followill; James K. Wolford; James V. Candy
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Paper Abstract

Sensor arrays offer opportunities to beamform, and time- frequency analyses offer additional insights to the wavefield data. Data collected while monitoring three different sources with unattended ground sensors in a 16- element, small-aperture (approximately 5 meters) geophone array are used as examples of model-based seismic signal processing on actual geophone array data. The three sources monitored were: (Source 01). A frequency-modulated chirp of an electromechanical shaker mounted on a floor of an underground bunker. Three 60-second time-windows corresponding to (a) 50 Hz to 55 Hz sweep, (b) 60 Hz to 70 Hz sweep, and (c) 80 Hz to 90 Hz sweep. (Source 02). A single transient impact of a hammer striking the floor of the bunker. Twenty seconds of data (with the transient event approximately mid-point in the time window). (Source 11). The transient event of a diesel generator turning on, including a few seconds before the `turn-on time' and a few seconds after the generator reaches `steady-state conditions'. The high-frequency seismic array was positioned at the surface of the ground at a distance of 150 meters (North) of the underground bunker. Four Y-shaped subarrays (each with 2-meter apertures) in a Y-shaped pattern (with a 6-meter aperture) using a total of 163-component, high- frequency geophones were deployed. These 48 channels of seismic data were recorded at 6000 and 12000 samples per second on 16-bit data loggers. Representative examples of the data and analyses illustrate the results of this experiment.

Paper Details

Date Published: 24 July 1997
PDF: 15 pages
Proc. SPIE 3081, Peace and Wartime Applications and Technical Issues for Unattended Ground Sensors, (24 July 1997); doi: 10.1117/12.280659
Show Author Affiliations
Fred E. Followill, Lawrence Livermore National Laboratory (United States)
James K. Wolford, Lawrence Livermore National Laboratory (United States)
James V. Candy, Lawrence Livermore National Laboratory (United States)


Published in SPIE Proceedings Vol. 3081:
Peace and Wartime Applications and Technical Issues for Unattended Ground Sensors
Gerold Yonas, Editor(s)

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