Ground Penetrating Radar- IDS Opera Duo

Ground Penetrating Radar- IDS Opera Duo

GPR is magic and should only be performed by masters of the dark art.

Often, we hear of similar sentences from all areas of the industry and to a point I do agree, because as with everything in life, the wrong tool in the wrong hands will not get you what you want. This has been the situation with GPR since it was massively over sold to industry as a “see all, glass bottomed boat that will give x-ray like results of the ground.” I’ve been using GPR for 20 years, and every day is still a learning day; that’s what keeps me hooked.

When I first used a GPR, I had no idea what it could do, or, to that point what it couldn’t do, how it did it, or why. As time has gone by, the kits have become much more user friendly, operating software has become much simpler to use with even expert or simple utility modes. Data can be collected today by an operator with only basic knowledge then passed on for interpretation to an expert back at base. Systems today are highly portable with every manufacturer offering a utility locating cart-based system that can access almost all areas. A mornings worth of training and away you go……right?

All manufacturer’s equipment follows the same basic principles of operation and is bound by the same physical laws:

1. The radar unit transmits a pulse of electromagnetic energy into the ground or medium being investigated through an antenna transmitter (TX).
2. The electromagnetic energy reflected back from any target, layer or object detected is recorded by the receiving antenna (RX).
3. The received signal contains information regarding position and depth relative to the transmit point. The time delay between send and receive signals is dependent on subsurface conditions which affect the velocity propagation of the electromagnetic energy wave
4. Data converted from audio to visual signal forms for display to user.

The penetration depth of any electromagnetic signal and its resolution depends on antenna frequency, the power of the electromagnetic wave transmitter, and the electrical properties of the ground it is transmitted into.* This applies to all GPR operations and is important for successful outcomes to your surveys.