The greatest technical challenge for the Military Munitions Response Program is the detection and classification of buried or sub-surface UXO. Investments focus on overcoming this challenge, an achievement that would enable DoD to conduct a more effective and efficient munitions response program.
The traditional process to identify and remove sub-surface UXO involves the following steps:
- a survey of the site using appropriate geophysical sensors
- analysis of the sensor data to identify anomalous responses above background
- construction of a “dig list” based on the analyses
- excavation of locations identified on the “dig list” and removal of all metallic objects.
The primary sensors used for these geophysical surveys are total-field magnetometers and electromagnetic induction sensors. These devices are deployed either singly or configured as arrays, and GPS or alternative geolocation methods are used to determine the locations of sensor readings.
At present, most munitions response projects use sensors that were originally developed for other purposes and adapted to the munitions response mission. Until recently, it has been common practice to dig every target on the detection list. The sensors function as metal detectors, so many of the detections on a typical site are not UXO, but instead are harmless buried metal or geology. In many cases, as few as one percent of the items excavated are actually hazardous.
Advanced analysis of the geophysical data allows an analyst to extract information about the buried target that can be used in a classification process. In most cases, this is accomplished by a process termed geophysical inversion. In geophysical inversion, the parameters in a response model are adjusted, using an iterative process, to obtain a match to the measured response. The estimated parameters can be used to classify detections into two categories: those that most likely arose from munitions and those that came from other, harmless, objects. This ability to classify the objects can pave the way for a more cost effective use of resources. SERDP and ESTCP are working to develop and demonstrate innovative technologies to improve the current process. The objective is to reduce costs while improving the effectiveness of UXO remediation for all types of munitions found on the wide variety of contaminated DoD sites throughout the nation. The key goal is to develop rigorous, effective, and transparent methods for classifying and distinguishing between harmless sub-surface scrap and dangerous buried UXO.
Projects focus on advancing the science and technology in the following areas:
ESTCP is conducting a series of demonstrations to validate and compare multiple advanced technologies and data processing techniques designed for the detection and classification of buried UXO. Each demonstration is conducted on a former or current military installation where UXO are known to be present, which is then seeded with inert munitions items. After the survey has been completed, all anomalies are excavated to confirm each technology's performance. Demonstrators are then scored based on their ability to eliminate nonhazardous items and identify all munitions. In addition to research firms, ESTCP is collaborating with production firms, regulators, and program managers to facilitate technology transfer. These studies are an ongoing effort that will span several years and tackle a wide range of site conditions, including a mix of munitions types, vegetation, and terrain.
Research on sensors aims to address deficiencies in detection and to provide better data to support classification. Efforts for improving detection include the development of smaller, lighter sensors that consume less power, which would enable the construction of sensor arrays and small, hand-held sensor systems for use in heavily vegetated areas. For classification, the focus is on developing next-generation EM sensors and systems that provide richer data sets exploiting shape and time decay information. Such systems would help classify a buried target as either a target of interest or a harmless item. A new generation of UXO-specific sensors is emerging from SERDP- and ESTCP-sponsored research.
Past projects involved developments in analysis of data from standard geophysical sensors. Several on-going projects involve the analysis of data from advanced electromagnetic induction sensors. These sensors provide much more information about the target from each measurement. They require new and more efficient ways to visualize and analyze the survey data. Once target parameters have been estimated from analysis of the survey data, a process is needed to support decisions about whether each item is likely to be a munition. Work is ongoing to improve the efficiency and performance of classifiers for use in munitions response.
Focus is on developing tools and methods to facilitate collection of high-quality geophysical data in all environments. Alternative geolocation methods and novel sensor deployment schemes are among the technologies being developed.