Ground Penetrating Radar (GPR)

Ground penetrating radar (GPR) uses a pulsed electromagnetic signal transmitted to and reflected by a “target” (re-bar, wire, moisture, layer interface, etc.,) back to the point of transmission.  The GPR wave transmission, signal velocity, and reflection are dependent on the electrical properties (dielectric constant and conductivity) of the material(s) being investigated. Material changes, such as asphalt to concrete, have sufficient difference in electrical properties to reflect Ground Penetrating Radar or GPR signals. And metal reinforcing and conduits are highly conductive and produce high amplitude (strong) reflectors of GPR signals. GPR results are qualitative and typically a depth determination is based on a site calibration.