GPR (Ground Penetration Radar) is used by a GPR surveyor as a non-destructive method of surveying for underground variations at a worksite. GPR Surveys can identify non-metallic as well as metallic subsurface objects, so can quickly locate utilities and services including water, gas, electric, fibre-optic, telephone and sewers without the need for any costly excavation.

This survey technique was originally developed to map geological features. Nowadays ground penetrating radar GPR is widely used to locate known and unknown supply lines buried underground. The data generated by a GPR survey is important information needed to avoid incidents that cause work stoppages. GPR surveys should be undertaken before projects are started.

Ground Penetrating Radar survey measurements can determine the overall construction layout, including the thickness of the pavement, depth and width of roads, bridges and other structures. GPR can detect cavities in the road surface and determine layer thicknesses, identify adhesive layers, determine the thickness of the road surface (asphalt, concrete, etc.) and identify and identify gaps in the road surface. Ground-based radar measurements can be used in a variety of construction projects such as road and bridge construction, road maintenance, road construction, roadsides, sidewalks, car parks and multi-storey car parks, as well as in urban and rural areas.

GPR data are used to assess the location and depth of buried objects and to investigate the impact of weather conditions on the Earth’s surface such as wind, rain and snow. GPR works by transmitting high-frequency radio waves (HRF) and low frequencies (LFR) to ground transformers (also called antennas).

Using GPR on-site, the antenna switch is pulled along the ground by hand or an all-terrain vehicle (ATV) and the penetration depth is also determined by the height of the GPR antenna used. GPR antennas are used to detect objects such as underground cables, pipes or voids, and can be used in buildings to locate other objects such as chimney flues. GPR can also be used in the construction of underground tunnels.

The effective penetration depth depends on the electrical soil properties and can be quite limited in moist clay for instance. GPR antennas at low frequencies (100 – 200 MHz) receive background reflections and have a low resolution. These low-frequency antennas are used to study the geology of rock layers, locate sinkhole fractures, delineate deep landfill ditches and clay caps, and locate large, deeply buried objects.

Using the lowest possible frequency gives a relatively high penetration depth. Frequencies up to 20 MHz can be used in deep caves or mine tunnels. A sufficiently high frequency must be selected for the wavelengths that are short enough to allow deep penetration into the Earth’s surface and high resolution for deep probes such as 1,000 kHz.

One example is that there are various GPR antennas that can be used for penetrating concrete when looking for a buried tank. These waves, which are used as electromagnetic waves on the ground, reflect underground structures and utilities and are thus detected. In GPR investigations, different wavelengths such as 100, 200, 300, 400, 500, 600, 800 and 1,000 MHz are used to detect function and depth.

Today, NDT (Non-Destructive Testing) surveying techniques are increasingly used in civil engineering and offer a much more accurate and accurate view of the ground than conventional ground radar surveys. GPR is the only non-destructive technology that can identify buried objects such as buildings, vehicles and other structures. Ground-based radar measurements can locate objects buried underground, at the earth’s surface or in underground caves or tunnels.

Ground-penetrating radar is a geophysical method that uses radar pulses to map the underground. This non-destructive method detects the reflected signals of underground surface structures and uses a combination of high-resolution imaging and low-frequency radio waves. Since the transmitted pulses are very short and are normally generated by transient voltage pulses from overloaded avalanche transistors, GPR is also referred to as pulse radar.