Ground Penetrating Radar (GPR) is useful in mapping and locating subsurface features. GPR is used to:
GPR uses a transmitting antenna that emits pulses of high frequency electromagnetic waves into the subsurface. The penetrating electromagnetic waves are transmitted downward and reflected by changes in the dielectric properties of the underground features to a receiver. GPR data can be collected continuously or at fixed station intervals. The result is a continuous cross-sectional profile. AGS has the ability to convert the recorded data into a three dimensional model. GPR has a practical depth range of 6″ to 80′ depending on soil characteristics. AGS is also one of the only companies in the United States with borehole radar capabilities. These capabilities allow subsurface investigation to depths of 500′.
GPR can provide a continuous display of data along a traverse which can be interpreted qualitatively in the field. GPR is capable of providing high-resolution data under favorable site conditions. GPR is often the only technology available for locating nonmetallic objects, such as fiberglass storage tanks, buried plastic drums, PVC piping, concrete sewer lines, and fiber optic lines.
Exploration depth can be limited by soil or water with high conductivity. Detection ability depends upon a dielectric contrast between the subsurface feature and the surrounding material. Closely spaced survey lines are required to locate small objects. A relatively smooth surface is also required.