Instrumentation for geognostic investigation
Georadar systems, better known as GPR systems (ground probing radar) are very useful both in geophysics for the study of the surface layers of the soil and in the building industry for the detection of such underground utilities as (ducts, water pipes or gas, etc.). The output the instrument provides is a section of the ground investigated from 1 meter up to several meters (about 10) according to the frequency of the antenna used to perform the survey. This method consists of entering short high-frequency electromagnetic pulses emitted by an antenna placed on the ground surface nearby the area to be investigated. During the depth propagation, if the electromagnetic pulse finds a surface which separates two parts having different physical characteristics, a part of the energy is reflected while the remaining one continues and passes through the second one. The waves reflected by the ground’s discontinuities return to the surface and are detected by the receiving antenna. The energy radiated from the transmitting antenna, and which is not reflected and moves beyond the discontinuity itself, may identify other anomalies (reflections) related to discontinuities located at greater depths. The instrument is moved progressively along a predefined survey area and you get a two-dimensional representation, "radargram", such as "displacement (along the way) / time (receiving signals reflected from anomalies during the survey) ".