Drift cancellation of an orientation tracker for a virtual reality head-mounted display

This paper presents design and implementation of a drift-free orientation tracker for head-mounted displays. The sensor consists of a 3-axis accelerometer, a 3-axis gyro, and a 3-axis magnetometer. A digital motion processor is also used. To remove gyro drifts in the long run, a sensor fusion method is applied that combines accelerometer, gyro, and magnetometer data. Before this data fusion, bias removal of accelerometer and calibration of magnetometer are carried out. The results of this sensor fusion are given to a virtual camera for real-time graphical rendering of the virtual environment. This program shows updates virtual images of the head-mounted display with 33 frames per second. The results show that the drift of gyro is reduced to less than 1.0 degrees over 3 minutes.