Distortion-robust distributed magnetometer for underwater pose estimation in confined UUVs

In this paper we describe a new approach to deal with dynamic distortions of the ambient magnetic field often leading to errors in orientation estimation in confined unmanned underwater vehicles. In such systems, the space to mount magnetometer sensors is strictly limited and the sensors are often in the vicinity of distortion sources like ferromagnetic material, sonar transducers or strong electric currents flowing through nearby supply lines. In our paper we describe a threefold approach to deal with these magnetic field distortions: the use of multiple distributed magnetometers for robustness, the use of very small pressure-neutral sensors to get rid of mounting restrictions inside pressure compartments and the development and application of a multi-magnetometer fusion algorithm using von Mises-Fisher (vMF) distributions to compute undistorted orientation information.