Ground penetrating radar works much like regular radar, using pulses of electromagnetic radiation in the microwave range and reading the reflected signal to detect subsurface structures and objects without drilling, probing or otherwise breaking the ground surface.

The range of the scan is affected mostly by the conductivity and composition of the ground; the resolution of the scan is affected by the scanning frequency. Higher frequencies do not penetrate as far as lower frequencies, but give better resolution.

Ground penetrating radar units must generally be in contact with the ground for best performance.