Drone GPR and magnetometry reveal buried features at a remote Mimbres site

The challenge

The site was once home to the Mimbres people. Despite two earlier excavations, much of it was unexplored. Northrop Grumman's Cultural Scans for an Interactive 3D Experience (SITEs) project aimed to record and investigate it digitally, but the team faced:

• little prior archaeological knowledge of large areas;
• high cost and effort to bring traditional equipment and people to the remote site;
• dense vegetation that blocked ground surveys and disturbed sensor readings;
• rugged, uneven terrain that risked patchy coverage and safety problems.

The solution

With support from SPH Engineering partners Measur and Altomaxx, Altomaxx flew a DJI M350 RTK carrying SPH Engineering's Zond Aero 500 GPR and MagDrone R3 magnetometer integrated systems. The site was split into ten areas, each flown in north–south and east–west patterns. Flights were piloted manually, with paths adjusted for vegetation and terrain. GPR lines were 1 m apart and magnetometer lines 2 m apart.

GPR data was processed in GeoHammer and Prism with filters to reduce vegetation noise. Magnetometer data was cleaned in the MagDrone Data Tool and analysed in Magneto. Results were combined with site maps in QGIS.

The results

• Magnetometry showed strong, well-defined anomalies in several areas, consistent with buried structures, voids or large human-made disturbance.
• At the Great Kiva and 200 Room Block, a high-intensity anomaly extended more than 4 m deep.
• GPR confirmed soil disturbance where vegetation was light, but was limited under dense vegetation.
• Where both sensors had usable data, overlapping anomalies pointed strongly to architectural features. GPR helped tell natural variation from built structures where magnetometry alone was unclear.

The report recommends adding aerial LiDAR next time, to map the surface under the canopy and help rank targets.

Where this applies in India

• non-invasive surveys of archaeological and heritage sites before excavation;
• remote or overgrown sites where carrying ground equipment is hard;
• heritage checks along new road, rail and pipeline corridors;
• archaeology and geophysics research at universities and institutes.

SPH Engineering's GPR training and magnetometer training are also available through HobiTech.

The equipment, available from HobiTech

Ground penetrating radar	RadSys Zond Aero 500
Magnetometer	SENSYS MagDrone R3
Onboard computer	Not named in the case study. We supply SPH Engineering integrated systems with SkyHub by SPH Engineering and the SkyHub GPR or SkyHub MagDrone software.
Drone	DJI Matrice 350 RTK
Processing	GeoHammer, Prism, MagDrone Data Tool, Magneto and QGIS

Case study by SPH Engineering, published August 2025. This page summarises it in our own words; the survey was carried out by Altomaxx with Measur for Northrop Grumman's SITEs project, not by HobiTech. Read the original case study on SPH Engineering ↗