Impact of interfacial dipole radiation on UXO target detection using 3-D Kirchhoff imaging

Ground penetrating radar radiation patterns are shown to effect array results on locating, and characterizing buried targets similar to those found in many unexploded ordnance scenarios. This is accomplished by comparing results obtained from physical experiments with theoretical dipole radiation patterns. Their experimental data uses 1.2 GHz mono-static resistively tapered dipole antennas precisely positioned in course rectangular grid over a 2- by 2by 1-m dirt filled box. The dirt fill is a silty river bank sand with a relative dielectric of 8.1. It contains a large number rocky inclusions. Buried at various depths are spherical and cylindrical bodies representing UXO and antipersonnel mines. These targers are a combination penetrable dielectric bodies and foil covered perfect reflectors. Their diameters range from 3 cm to roughly 7 cm. They apply mono-static 3D Kirchhoff migration to the data. Their results show that low contrast near surface targets including air filled, plastic, and metal targets can be resolved both vertically and horizontally when array coverage considers the dipole radiation pattern. Deeper cylindrical targets are also observed just above a bottom layer interface. Results from the deeper targets are less affected by individual antenna orientations