These methods have inherent problems, ground magnetics is slow and expensive to acquire and while being the highest resolution when acquired the magnetic data is almost always very noisy due to taking the magnetic measurements very close to surficial magnetic material and has to be heavily filtered, this surficial noise and filtering destroys the fine scale or subtle geological response in the data. Airborne magnetic data has far less noise than ground collected magnetic data, but, depending on the topography it can be very difficult to follow the terrain correctly and keep the aircraft at a constant height above the ground using a fixed wing aircaft, this results in artificial variations in the measured field strength due to the height variations as well as partial or complete loss of fine scale and subtle magnetic response when the aircraft is forced to fly higher above the ground due to steep or difficult terrain.

A helicopter with a magnetometer mounted on a boom or stinger can be used to fly difficult terrain better than a fixed wing but the magnetic data from a stinger mounted magnetometer is notoriously noisy due to the close proximity of the magnetic sensor to the rotating metallic components and electronics of the helicopter. As well as the inherent data quality issues with conventional airborne surveys there is also a large element of danger with the safety of the pilot (and system operator if onboard) and the large asset value of the aircraft at high risk when flying very low levels, each survey demands an exhaustive risk assessment before commencing, and even then numerous aircraft and lives have been lost over the years.

A UAV mounted system solves the problems above, particularly if the magnetometer is housed in a towed bird that flies at a distance below the UAV and its engine and electronics reducing or eliminating any aircraft induced noise in the data. A rotary wing UAV can fly with practically zero risk to human safety, at a constant height above the ground and can follow the terrain regardless of the topography, the height of the tree canopy and any structures in the survey area being the only constraint with regards to minimum sensor height. Using a UAV and towed magnetometer bird to collect magnetic data allows magnetic data resolutions at close to ground survey resolutions, without the inherent safety, noise, or terrain following issues inherent to ground or conventional airborne surveys.