Celtic cut and core use the conquest 100 for their concrete scanning projects:
The Conquest 100 Ground Penetrating Radar (GPR) is designed for safe, non-destructive evaluation of concrete structures. Conquest offers rapid on-site imaging for cutting, coring, drilling, or the characterization of concrete slabs with limited or missing design drawings.
The Conquest 100 uses radio waves to locate objects of differing dielectric constant, therefore materials such as plastics, metals, and filling material can be located inside the concrete.
The system can scan concrete to depths of up to 0.5m where a cover meter would be limited to 150-200mm.