Ground Penetrating radar, or GPR, is used for locating objects or voids within a solid or dense environment. The uses for this technology are virtually limitless. By sending repeated radar signals along the ground or a wall, the speed and intensity of the echoing signals are measured. Each signal is transformed into a 2D image. Several of these 2D images, taken from different angles, may be transformed to a 3D image. This 3D image reveals the approximate size and shape of a subsurface object, the change in density of the ground, or something as simple as a pipe in a wall.

Ground penetrating radar is operated as a cart that can be moved over the ground or a hand held device for vertical scanning of a wall. The size of the antennas, ranging from 100MHz to 2000MHz, determines the penetration capabilities and sensitivity of the equipment.  For example a 500MHz is most widely used for locating underground utilities and 1000MHz is best for locating pipes and rebar within walls. GPR is capable of seeing through all non-conductive materials. Conductive materials like metal and salt water do not allow penetration and return a very strong signal.  Although it is impossible to determine exactly the speed that the GPR travels through the ground, due to inconsistent composition, it can generally be estimated within a margin of error of plus or minus 10%.

Some of the many and diverse uses for ground penetrating radar are as follows:

  • Utilities – Locating pipes, cables, manholes, missing valves, illegal or unknown connections
  • Structural – Slab, wall or layer thickness, reinforcing, cracking, water intrusion and voids.
  • Geophysical – Ground water, strata layers, buried wood, boulders, rocks and bedrock, root mass, disturbed soil and density changes.
  • Archaeological – Location of artifacts and structure mapping.
  • Environmental – Buried drums, landfill areas and limits and high saturation limits.
  • Military – UXO (unexploded ordnance such as mines or IED), bunker and tunnel locations, buried weapons caches and casualty burial sites.
  • Law Enforcement – Locating contraband, forensic investigation, objects such as weapons, or stolen property, hidden in walls or beneath floors and buried caches.

Ground penetrating radar is user friendly, requiring easy training that can be mastered by persons in any occupation. Most operators learn how to make accurate readings within a single day. It is non-destructive and non-disturbing, making very little noise. It is also very rugged and durable being able to withstand the most demanding environments. As a tool for preventing the complete upheaval of property or partial demolition of buildings while searching, GPR is invaluable.  Without it, many crimes would go unsolved, military and civilian lives would be lost and history would remain hidden.