Reducing magnetic interference in a geomagnetic survey UAS through modelling and design optimization

This paper presents modelling and optimization strategies to minimize electromagnetic interference in an Unmanned Aircraft System (UAS), GeoSurv II, intended for geomagnetic surveys. The Direct Dipole Model (DDP) and Modified Dipole Ellipse Model (MoDEM) were proposed and tested to model on-board magnetic sources. MoDEM proved to more accurately represent magnetic interference sources. These models were validated experimentally and utilized to minimize interference within regions around wingtips where magnetometers are installed. A new strategy, called Optimal Field Attenuation (OFA), uses the total magnetic interference calculated within a region of interest as the objective function to find an optimum design configuration (position and orientation of the sources). The OFA algorithm was experimentally validated and proved effective in its dramatic reduction of magnetic interference.