ABSTRACT
Ground-penetrating radar, often referred to as GPR, is an active electromagnetic subsurface investigative method. Its operation is based on the introduction of a relatively low-frequency electromagnetic signal, generally in the 10-1000 megahertz (MHz) range, into the ground via a transmitting antenna in contact with the ground. As this signal penetrates into the earth, it will be reflected, refracted, and/or diffracted as it encounters materials of contrasting electrical properties (Figure 6.1).
