Electromagnetic Ground Penetrating Radar (GPR) method is widely used in geological and infrastructure investigations. The method allows the soil, rock and infrastructure subsurface imaging in non-invasive manner. The method is based on the GPR signal interaction with the the medium. When the transmitted signal reflects back to the receiving antenna, GPR profile is formed. The electrical changes in the medium causes response into the GPR profile. Such electrical changes are related to the material changes in the soil, change of water content, overburden-rock interface or rock mass fracturing. There are many applications for the GPR method, some have yet to be invented.
The ground penetrating radar equipment consists of a central unit, an antenna, a distance encoder and the necessary cables. Measurement can be performed by one person, but on the basis of the workman safety, we implement the measurements in a group of two. Measurements can be made by moving the antenna either manually or pulling the antenna in sled by foot, skis, snowmobile, ATV or car.
The research depth is influenced by the center frequency of the GPR antenna and the electrical properties of the medium to be measured. The GPR antenna is selected on the basis of the investigation target. Central frequencies of the antennas cover the range from 50 MHz to 2.6 GHz. At high frequencies antennas, the investigation depths are less than one meter and low antenna frequencies up to tens of meters.
The data can be monitored during the measurement, enabling the real-time locating of the subsurface objects already on site. The data is also stored in the memory of the central unit. Data can be transferred to the computer for further analysis. Processing, interpreting and rendering of resulting profiles is done with specialized GPR software.
The most common product obtained by the customer for the research project is the ground penetrating radar profile image with the interpretations. Detected objects and interfaces as well as their depths can be viewed from the profiles. If necessary, the result can be tied to the measurement line length or location information according to the customer’s needs.