US Patent 10067560 Head tracker for dismounted users

A head-tracking system for dismounted users comprises an inertial georeferenced head tracker (IGHT) having a time-cumulative drift error, an azimuth-referenced head-tracker (ARHT), and a controller. The ARHT comprises a data link with an angle of arrival antenna, differential global position satellite receivers, and a processor configured to determine the head position of the user and initialize the IGHT. The controller may compare a current drift error of the IGHT with a predetermined drift error threshold. If the current drift error is below the predetermined drift error threshold, the IGHT data may accurately represent the head position of the user. If the current drift error is above the predetermined drift error threshold, the IGHT may be updated with the ARHT data to accurately represent the head position of the user.