What can Ground Radar detect?

Ground Penetrating Radar (GPR) can effectively be used to locate and distinguish a wide variety of metallic and non-metallic materials. Ground Radar works best when there is a big difference in the electromagnetic properties of the materials being surveyed. For this reason metallic objects make ideal targets (e.g. reinforcement within concrete). Ground radar will however detect most materials providing there is a sufficient difference in the electromagnetic property between the target and surrounding material. Some of the more common target materials include:

• metal
• plastics
• changes in ground strata and geological features
• concrete
• air pockets or voids

Excavated areas, back-filled areas and any other ground disturbances can also be identified and mapped.

Ground Radar will not work in certain ground conditions such as heavy clay soils, particularly if they are waterlogged. De-ionised water does not pose a problem to Ground Radar, however water with a high mineral content (e.g. sea water) absorbs much of the signal making it an unsuitable medium. Ground Radar is also unable to see "behind" metallic objects, including dense reinforcement.

It should be remembered that Ground Radar is a relative method. It detects changing conditions from the surface down but does not determine the absolute nature of the materials surveyed. It may be necessary to supplement the Ground Radar data with absolute data from boreholes, sample cores, trial pits, etc.

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