Discrimination of UXO in soil using broadband polarimetric GPR backscatter

Abstract

Abstract-Polarimetric analysis of ground penetrating radar (GPR) backscatter offers a new means of discriminating subsurface metallic target shapes from one another. Such discrimination is urgently needed to distinguish buried unexploded ordnance (UXO) from other subsurface objects. To illuminate the underlying phenomenology of scattering from objects enveloped in soil, three-dimensional (3-D) simulations are performed over a broad frequency band, characteristic of new low frequency GPRs. For moist soil, this means that the subsurface wavelength may range from a fraction of the target size to an order of magnitude larger. With a transmitting antenna representation that produces typical subsurface GPR beam features, combined effects of positional, orientation, and frequency diversity are investigated. Despite long wavelengths, results show distinctive features in reflections obtained from contrasting example target shapes. Full polarimetric analysis suggests the capability for inferring the length of elongated targets, aspect ratio and rotational symmetry, and gross shape along the axis for either elongated or flattened bodies of revolution in problematical orientations.

Effects of the ground surface on polarimetric features of broadband radar scattering from subsurface metallic objects

“…The second phenomenon of interest, induced field rotation and ellipticity in the backscattered signal, is also demonstrated in our preceding paper [9]. For clarity we settle here on two definitions:…”

“…In closely related preceeding work we calculated certain basic, revealing features of scattering from relevant finite target shapes in moist soil [9]. These were computed assuming, as in what follows here, that the relative permittivity of the soil is 10.4 and its electrical conductivity is 2.8 x 10 -3 (S/m), corresponding approximately to conditions in a damp, fine grain soil at particular UXO test site.…”

Independent component analysis for UXO detection in highly cluttered environments

“…Collins et al, 2000;Gao et al, 2000;Norton and Won, 2001;Tantum and Collins, 2001), ground penetrating radar (GPR) (e.g. O'Neill, 2001), magnetometry (e.g. Billings, 2004) and seismic sensors.…”

UXO Discrimination Using Blind Source Separation

“…Several sensor modalities are currently being used for detection and identification of subsurface objects (UXO), such as electromagnetic induction (EMI) (Norton & Won, 2001), ground penetrating radar (GPR) (O'Neill, 2001), magnetometry (Billings, 2004), and seismic sensors. Historically, EMI sensors have been used extensively to locate buried landmines and UXO by detecting the metal present in such targets.…”