GPR equipment is capable of transmitting and receiving electromagnetic waves which are sent into the grounds subsurface or other material, and detects interfaces between differing materials. The interface between these materials are identified by the changes which occur to the electromagnetic waves. These changes can be caused by voids, reinforcing bars, underground utilities (metal or plastic), conduits, or a variety of other items. The antenna transmits and receives a high-frequency electromagnetic impulse (radar wave) into the material of interest, and records the travel time and amplitude of the reflected impulses.