GPR TECHNOLOGY

Ground penetrating radar (GPR) is a geophysical method that uses radar pulses to image into the subsurface. This nondestructive method uses electromagnetic energy in the microwave band (UHF/VHF frequencies) of the radio spectrum, and detects the reflected signals from subsurface structures.

GPR uses multiple FCC approved high-frequency radio waves, usually in the range 10 MHz to 2.6 GHz. A GPR transmitter emits electromagnetic energy into the ground. When the energy encounters a buried object or a boundary between materials having different dielectric constants, a potion of the propagated energy is reflected or refracted back to the surface.

The reflected radar energy is then detected back at the surface by a receiving antenna and converted to electrical signals, which correspond to minor changes in the voltage. The signals are sent to the control unit, amplified, and recorded. These recorded signals are then sent to a field laptop computer and a real-time two-dimensional depth profile is constructed. From the depth profile, features such as subsurface utilities, pipes, voids, structural reinforcement, conduits, and/or other obstructions may be interpreted and located in the field.