Wide-Area Assessment (WAA)
Description
Wide
Area Assessment is a characterization strategy using a variety of platforms to
cost-effectively delineate areas where unexploded ordnance (i.e., bombs and
shells, or UXO) is likely to be found on the vast munitions ranges throughout
the United States. By narrowing the footprint of potential UXO locations, WAA
saves times and money on conventional characterization.
Conventional
detection and characterization technologies involved hand-held magnetometers
operated by technicians who must slowly walk across a survey area, or using a
towed array of sensors that is driven across an area. These methods can be
utilized more efficiently after after high-level aircraft take high-resolution
photographs to detect topographic anomalies and low-altitude helicopters
(flying about three meters above the surface) delineate magnetic anomalies.
At
underwater sites, high altitude aircraft are not used; rather the area is
subjected to both an assessment by low-altitude helicopters and additional
assessment by a marine towed arrays to detect magnetic anomalies underwater.
Limitations
and Concerns
No
existing technology for characterizing buried UXO achieves the 100% detection
rate sought by many neighbors of military property containing UXO, though they
approach that for items on or just below the surface. Wide Area Assessment is a
tool that focuses on detecting areas with high concentrations of munitions, not
one single target.
Data
interpretation is a key to the success or failure of this technology.
Magnetic
and electromagnetic detectors have diminished accuracy in highly magnetic
soils. High-density magnetic clutter can make it nearly impossible to locate
target areas.
Where
vegetation exists or topographic anomalies exist such that aircraft or towed
arrays cannot be used, handheld magnetometers must be used. Often the areas are
so vast that this step does not take place.
Man-made
alterations of the surface (or on the surface) may obscure detection of UXO.
Physical
access to a developed site may be problematic (e.g., right of entry, fences,
power lines, recreational activity).
Underwater
UXO location does not have the same level of confidence. In a marine
environment, the distance between the array and the targets will increase by
the water depth, so only large munitions are detected at any reasonable
efficiency.
The
tools used in Wide Area Assessment do not replace the need for historical
research.
Applicability
The
U.S. Department of Defense (DoD) is responsible for over 15 million acres of
weapons ranges in the United States, and over 1,500 sites may require the
cleanup of UXO. Wide area assessment is an advanced characterization technique.
Technology
Development Status
Wide
Area Assessment has been proven and is used by the DoD. The marine systems are
in the pilot stage of development.
Web
Links
http://www.serdp-estcp.org/Featured-Initiatives/Munitions-Response-Initiatives/Wide-Area-Assessment
http://www.itrcweb.org/Documents/UXO-6.pdf
Other
Resources and Demonstrations
http://www.serdp-estcp.org/Program-Areas/Munitions-Response/Underwater-Environments/MR-1631
http://www.serdp-estcp.org/Program-Areas/Munitions-Response/Underwater-Environments/MR-200606
See the
description of the Multi-Sensor Towed
Array Detection System.