Ground penetrating radar incorporating a real-time multi-target direction finding capability

Abstract

The Ground Penetrating Radar (GPR) system introduced in this application provides data from an underground medium of the same caliber as that provided by conventional radars in air or space applications. This includes direction as well as distance to all targets, and some indication of target shape and orientation, within a conical volume of the underground having a solid angle of about 90 degrees and a radial depth of about 100 feet, under ideal conditions, as depicted in FIG. The key to this capability is depicted in FIG. and is a hemispheric dome ( ) which is placed against the smoothed surface ( ) of the underground medium ( ), and which has a relative dielectric constant (E ) substantially equal to that of the underground medium ( ). A microwave horn antenna ( ), which is filled with the same dielectric material ( ) as that from which the dome is constructed, is placed against the surface ( ) of this dome ( ) and is moved back and forth ( ), allowing the radar beam ( ) of the horn antenna ( ) to systematically scan the entire conical volume. The signal path of this radar antenna system is thus completely within a dielectric material having an (E ) comparable to that of the underground medium, from Coax-to-Waveguide transition through to the potential underground targets. No air-to-dielectric interface, with its reflections and refractive lensing effects, remains.