The most important parameter of the GPR system is the center frequency. In general, it defines the maximum penetration (if the power of impulse doesn’t exceed allowed limits in most countries) and also resolution and capability to detect objects of a certain size.
Airborne GPR applications and practical considerations
Below is a summary of what we can expect from the GPR systems available for use with drones and
their recommended applications. Here we listed GPR systems manufactured by Radar Systems Inc.,
Latvia, but any other GPR systems with similar center frequency will have more or less the same
practical parameters in terms of penetration and resolution.
Please note that the actual penetration in certain places depends on dozens of factors – composition of the soil, humidity, temperature etc. In the table below, we used the parameters of a typical “average soil” – some substance with the relative dielectric permittivity of 9, low conductivity, not saturated.
Due to the fact that in case of airborne use (when GPR antenna is not in contact with the surface) a significant part of GPR impulse energy can be reflected back from the surface, expected penetration from a drone is half of that achieved with terrestrial survey on the surface. Recommended altitude (or the distance between the antenna and the surface) in case of airborne survey should be less than the length of EM wave in the air corresponding to the center frequency of the antenna.
Penetration in good conditions like very dry sand in desert after the dry season can be up to 2 times better. In ideal conditions (snow and ice) penetration can be 3-4 times better. Conditions like dry sand or snow/ice are also very good for airborne use: if the recommended altitude is maintained we don’t see any significant degradation of maximum penetration.
Zond Aero LF GPR systems by request may come with antennas for lower/custom center
frequencies. Please ask for information.
