Sub-Audio Magnetics; Miniature Sensor Technology for Simultaneous Magnetic and Electromagnetic Detection

MR-200322

Objectives of the Demonstration

Experience in detection of unexploded ordnance (UXO) has seen the overwhelming adoption of digital electromagnetic and magnetic sensors. Each has its advantages and disadvantages. Those seeking the highest standards of detection and remediation performance demand that both be used and only accept analytical discrimination between UXO and non-UXO targets that is defensible. Those funding UXO remediation recognize the need for a single-pass sensor system that can be used efficiently in all terrain conditions, satisfy detection standards at least equal to a combined electromagnetic and magnetic search, and deliver data from which false alarms may be minimized without compromising UXO detection. This project will demonstrate and validate a sensor technology with the potential to reduce UXO remediation costs by enhancing detection performance and delivering discrimination against false alarms that will satisfy regulators.

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Technology Description

Sub-Audio Magnetics (SAM) is a patented method by which a total field magnetic sensor is used to simultaneously acquire both the magnetic and electromagnetic response of subsurface UXO. A wire is first laid along a "meandering loop of convenience" surrounding the area to be searched, which may be several acres in size. A time-varying current then is transmitted at a sub-audio frequency of typically 32 hertz. Total field magnetic measurements are acquired at a rate of up to 8 kilohertz while systematically traversing the area within the loop as for a conventional magnetic survey. Post-processing then separates the total magnetic field intensity and the total field electromagnetic transient response. Both are mapped to the position where the measurement was acquired using a Differential Global Positioning System or alternate positioning technology.

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Implementation Issues

SAM has the potential to significantly exceed the individual detection performance (i.e., reliability and depth) of both magnetics and electromagnetics. Joint inversion of independent, co-registered response parameters will deliver discrimination capability not possible from a single detection parameter response, without compromising UXO detection. Achieving a higher probability of detection and a defensible discrimination performance from a single-pass, highly portable detector system will result in the total cost of UXO remediation being significantly reduced through improved search efficiency and a reduced rate of false alarms.

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Project Documents

Points of Contact

Principal Investigator

Mr. Lynn Helms

Huntsville-Army

Phone: 256-895-1625

Fax: 256-895-1602

Program Manager

Munitions Response

SERDP and ESTCP

Project Documents

Document Types

  • Fact Sheet - Brief project summary with links to related documents and points of contact.
  • Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
  • Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
  • Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
  • Guidance - Instructional information on technical topics such as protocols and user’s guides.
  • Workshop Report - Summary of workshop discussion and findings.
  • Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
  • Model/Software - Computer programs and applications available for download.
  • Database - Digitally organized collection of data available to search and access.