Wearable Magnetic Field based 3D-Orientation and -Position Acquisition

This paper introduces a new magnetic field based system design for 3D-orientation and -position acquisition in mobile applications for human motion analysis. The system basically consists of a source unit and a sensor unit and does not require any line of sight between its components. The source unit contains a single one-axis coil for magnetic field generation as well as a MARG sensor for 3D-orientation estimation. The sensor unit contains a single MARG sensor both for 3D-orientation and 3D-position estimation. For 3D-position estimation, a new algorithm is proposed which exploits not only the magnitude of the coil generated magnetic field, but also the phase information and thus is able to determine a unique position solution based on the data of a single 3D-magnetometer only. A wearable prototype of both the source and the sensor unit is realized and used for system verification by comparing the position data of the prototype to the data of a camera-based reference system (Vicon Vero). The verification results indicate high accuracy and repeatability of the proposed system.