Drone Geophysics for Ground Investigation and Geotechnical Site Assessment

No, and you should not buy one on that basis. Geophysics gives you continuous coverage with interpreted results. Boreholes give you samples, in-situ testing, and ground truth at a point. The productive workflow runs the drone survey first, then places the boreholes on the anomalies and layer transitions the survey identified, which usually means fewer holes in better locations.

It depends on antenna frequency and ground conductivity. In dry, low-conductivity soils, penetration from a drone runs roughly 1 to 2 m at 500 or 600 MHz, 2 to 4 m at 300 MHz, 4 to 8 m at 150 MHz, and 7 to 10 m at 100 MHz. Because part of the pulse reflects off the surface before entering the ground, airborne penetration is typically around half of what the same antenna achieves ground-coupled. Dry sand can roughly double the range, and wet clay can cut it to almost nothing.

Cavity and sinkhole search is a standard application for Zond Aero systems from 600 MHz down to 100 MHz. Detection depends on void size relative to depth: as a working rule, a reflector should be at least 10% of the antenna-to-target distance. Plan with margin rather than at the limit, and treat a clear result as a screening outcome, not a certification.

Clay and clayey soils are among the worst mediums for GPR, and even a thin damp clay layer can block most of the signal. Saturated topsoil after rain has the same effect. On clay-dominated sites, schedule late in the dry season, or use magnetometry instead if the targets are ferrous.

Yes. Zond Aero 500 NG, 600, and 1000 NG mount on drones and fit wheeled carts, and Zond Aero LF has monostatic and bi-static terrestrial survey kits. The unit, data format, and processing workflow stay effectively the same. That matters on projects with both an open greenfield area and confined sections around existing structures.

SkyHub and the sensor payloads integrate with DJI M400, M350 RTK, M300 RTK, and M600, Inspired Flight IF1200A and IF800, Harris Aerial H6, Wispr Ranger Pro, and Cube or Pixhawk platforms running ArduCopter or PX4. Mounting hardware is included for supported models. SPH Engineering supplies the sensors, integration, and software, not the aircraft.

No. We supply the complete system with training, certification, and support so your team runs the surveys. We do provide limited data processing assistance to help set up your workflow and transfer knowledge to your staff.

Standard GPR outputs are vertical profiles along each survey line, horizontal depth slices, thickness grids for overburden or layer thickness, and 3D reconstructions, all exportable to QGIS, ArcGIS, and CAD. Magnetic surveys produce anomaly maps and target lists with depth and mass estimates. Datasets can be stored, compared across survey dates, and shared through a browser in DroneGIS.

Match the method to the target. GPR detects layer boundaries, voids, and both metallic and non-metallic objects, so it is the method for stratigraphy, rockhead, and cavities. Magnetometry only detects ferrous material, but it covers ground faster, works over vegetation better than GPR, and reaches large steel targets at several metres. On sites where both buried steel and unknown layering are concerns, running both over the same grid gives the most complete picture.

Iron and steel. Old foundations with reinforcement, buried tanks, cased wells, steel pipes, reinforcement mesh, and unexploded ordnance all produce magnetic anomalies a drone-mounted sensor can map. Magnetometry is blind to non-metallic targets, so it will not find a concrete duct, a clay pipe, or a layer boundary. Depth reach scales with target mass: a large steel tank shows at several metres, while a single small item only registers near the surface. Processing in Magneto or Oasis montaj turns the anomaly map into a target list with depth and mass estimates for the earthworks contractor.