There are two main types of GPR systems: traditional time-domain pulse systems and SFCW (Stepped-Frequency Continuous-Wave) frequency-domain systems. The radar antennas are normally categorized in two groups: air-launched antennas and ground-launched antennas.
Ground penetrating radar (GPR) is a geophysical method based on a transmitting antenna radiating short pulses (usually polarized) of radio waves into the ground (or a concrete surface). When the wave finds a change in the electromagnetic properties of the propagating medium (soil, rock or concrete) the receiving antenna records variations in the reflected return signal.
The frequencies of the electromagnetic pulses vary according to the type and model of the antenna (from 25 MHz to 4 GHz). Information about depth and character of anomalies are obtained from the travel time and amplitude of signals. It is a methodology that requires skilled data processing, experience and a profound theoretical knowledge about geophysical wave theories and methods.
Modern systems can be divided as single channel (one recording sensor) o multichannel (several sensors recording simultaneously as an array). The use of multichannel arrays speeds-up acquisition times making it possible to cover large areas with unprecedented data density.
- Single-channel Ground Penetrating Radar (GPR2D)
- Multichannel Ground Penetrating Radar (GPR3D)