Aspects of heading determination via fusion of inclinometer and magnetometer data

The development of a system for heading determination of a small underwater vehicle is described. The system uses a Kalman filter to fuse information from a pair of inclinometers and a tri-axial magnetometer. The magnetometer can be corrupted by variations in the Earth's field caused by: external objects and internal magnetic fields. The internal field is assumed to consist of static and thruster dependent parts. We show how to use inclinometer data to adjust for a limited set of external field variation. We also show how to calibrate the magnetometer to compensate for static and thruster dependent internal fields.