The efficiency of unexploded ordnance (UXO) remediation is currently limited by the inadequate discrimination capability of present detection technologies, such as single sensing coil inductive sensors. While these methods often detect all relevant metal objects, they generally cannot discriminate between harmful objects and harmless clutter. False indications continue to far outnumber verified detections. To help address the need for a fieldable detection and clutter suppression capability, high resolution inductive arrays are being developed for UXO imaging. This development effort leverages existing MWM(R)-Array sensor and instrumentation technology used in nondestructive testing to create quantitative images of geometric and material property variations. This program is being funded by SERDP and JENTEK Sensors. This paper reviews the MWM-Array technology and its extension to UXO detection and discrimination. The technology uses unique designs for electromagnetic induction sensor arrays incorporating a single drive with multiple sense elements. The drive creates a shaped magnetic field pattern that concentrates the field energy into longer wavelength spatial modes for deeper and "focused" penetration into the ground. Arrays of small inductive coils, placed throughout the shaped field, sense the response from conducting or magnetic UXO and clutter. Images obtained from scans over buried objects provide a basis for spatial filtering and signal processing. Multiple sensor arrays placed at different positions within the drive provide different "views" of buried objects and clutter. Model-based grid measurement methods are also reviewed as a real-time method for multiple property measurements, and real-time data analysis/image generation.
