Suppression of surficial maghaemite magnetic noise using an Unmanned Aerial Vehicle deployed magnetometer

Data from two areas in the Tennant Creek mineral field that were recently flown with a magnetometer towed below an Unmanned Aerial Vehicle (UAV or "drone") using a sensor height of 15–20 m above ground are compared to older datasets acquired on the ground and in the air. The ground data are shown to be severely affected by surficial maghaemite, creating significant noise degradation of the ground data. Conversely, regional data flown at a height of 60 m above ground level only produces very subtle anomalies over the targeted features that could be easily missed by interpreters. Low-level, high-resolution UAV data shows significant improvement in signal-to-noise equivalent to upward continuation: filtering out the surficial signals while retaining excellent detectability of small subsurface ironstone targets, and significant gains in surveying efficiency over both ground and airborne operations.