Ground Penetrating Radar (GPR) employs radio waves, typically in the 100 MHz to 2.1 GHz frequency range, to map the internal structure of materials. Electromagnetic waves propagate into the subsurface via the radar antenna and reflect off objects or boundaries with differing dielectric permittivity and electrical conductivity than the host material. Materials with a high contrast in permittivity, such as soil/air, concrete/soil, and steel/soil, allow for detection of these changes. Vertical structures, such as walls and columns, can also be evaluated using GPR. A variety of radar antennas is available to target dimensions for optimum detection and imaging.