Vertical gradient of the geomagnetic field by multiple altitude aeromagnetic survey

Modern geophysical survey technologies are progressing fast. One notable milestone of this progress is substantial increase of georeferencing performance with benefits of advanced satellite radionavigation. This article delves into the advantages of employing multiple altitude (also referred to as multilevel) aeromagnetic measurements conducted using unmanned aerial vehicles for deriving vertical gradient. This approach contrasts with conventional methods that rely on the calculation of the corresponding transform of the anomalous magnetic field. A comparative analysis was conducted on two study areas, characterized by distinct magnetic anomalies. One region exhibited strong anthropogenic disturbances against a background of a relatively calm regional magnetic field, while the other demonstrated weaker anthropogenic anomalies. The comparison between the maps of the anomalous field gradient calculated directly and derived from multilevel survey in both regions underscores the potential benefits of straightforward gradient measurement methods.