Ground Penetrating Radar

Ground penetrating Radar (GPR) is widely used for investigation of the ground surrounding, and the composition and integrity within, engineered structures, such as buildings, bridges, earthen dams and road beds.
GPR systems typically include a radar pulse generator, transmitter, receiver, antenna and equipment for electronic data acquisition and storage. The electromagnetic radar pulse propagates into the data acquisition and storage.
The electromagnetic radar pulse propagates into the specimen, and wave reflection occurs at localized changes in dielectric properties.
Test frequency generally varies between 500MHz and 2GHz. Higher frequencies allow for shallow interrogations at high resolutions; however, resolution must be sacrificed when the penetrating ability of lower test frequencies is required.
Position encoder for Data.
Data collection is usually triggered by position encoder, such as a survey wheel. The encoder triggers data acquisition at regular intervals. Individual waveforms collected along the path of the radar antena can be viewed collectively in a B-scan data presentation

Depending on the application, systems are described as either ground-coupled or air-coupled. Air-coupled or-launched systems use antennae positioned at or above a height related to the centra test frequency, whereas most ground-coupled antennas are positioned with the housing directly in contact with the ground. Air-coupled systems offer higher inspection speed, but ground coupling offers greater depth of penetration at a given test frequency.