Penetrating Radar x (GPRx) is the general term applied to techniques which employ radio waves, typically in the 3 KHz to -7 GHz MHz frequency range, to map structures and features buried in the ground (or in man-made structures). Historically, GPR was primarily focused on mapping structures in the ground; more recently GPR has been used in non-destructive testing of non-metallic structures.

The concept of applying radio waves to probe the internal structure of the ground is not new. Without doubt the most successful early work in this area was the use of radio echo sounders to map the thickness of ice sheets in the Arctic and Antarctic and sound the thickness of glaciers. Work with GPR in non-ice environments started in the early 1970s. Early work focused on permafrost soil applications.

GPRx applications are limited only by the imagination and availability of suitable instrumentation. These days, GPRx is being used in many different areas including locating buried utilities, mine site evaluation, forensic investigations, archaeological digs, searching for buried landmines and unexploded ordnance, and measuring snow and ice thickness and quality for ski slope management and avalanche prediction, to name a few.