Ground Probing Radar – GPR

Ground Penetrating Radar (GPR) is used in environmental, archaeology and construction projects. GPR is an electromagnetic pulse reflection method for shallow investigations (normally < 20 m) with high vertical resolution (ca 0,01-1 m). Electromagnetic pulses are transmitted into the ground. The velocity of the radar waves are mainly controlled by the electrical properties in the ground and are highly sensitive to changes in water content. A part of this energy is reflected or scattered at layer boundaries with different electrical properties, e.g. rock strata, the water table or at buried objects. The amplitudes of the direct and reflected waves of the electromagnetic field are recorded as a function of traveltime in a radargram. The frequency of the antenna is chosen depending on the size of and depth to the target. High frequencies, i.e., short wavelengths, provide a higher resolution. On the other hand, due to higher absorption and scattering, signals with higher frequencies have less penetration depth than that with lower frequencies. The survey can be carried out on the ground by a walking person or attached to a car or a snowmobile. GPR provides profiling results in real-time in the form of a radargram on a monitor. In many cases, a preliminary interpretation is possible directly in the field.

Reference projects

– Search for caves on Gotland
– Rock surface level in Malmberget
– Water depth in Vittangi
– Search for water pipe in Kiruna