Aeromagnetic Surveying with Unmanned Aircraft Systems

UASs have been under rapid development for applications in the mineral exploration industry, mainly for aeromagnetic surveying. They provide improved detection of smaller, deeper and weakly magnetic targets. A traditional system flying an altitude of 100m above ground level can detect a spherical ore body at a depth of 40m and magnetic susceptibility of 10-4, with a radius of ~16m. A UAS flying at 50m or 2m altitude AGL would require the radius to be 11m or 5m, respectively. Using the Venturer fixed-wing UAS and the SkyLance rotary-wing UAS, two aeromagnetic surveys were performed. The Venturer was stable in flight with a fourth difference noise level within industry standards of ±0.05nT. A magnetic map was produced showing local variations. The SkyLance flew over a zinc deposit with 3 magnetic anomalies. It produced repeatable data that compared well with upward continuation maps of ground magnetic data.