Head-tracking and subject positioning using binaural headset microphones and common modulation anchor sources

A prerequisite in many systems for virtual and augmented reality audio is the tracking of a subject´s head position and direction. When the subject is wearing binaural headset microphones, the signals from them can be cross-correlated with known sound sources, called here anchor sources, to obtain an accurate estimate of the subject´s position and orientation. In this paper we propose a method where the anchor sources radiate in separate frequency bands but with common modulation signal. After demodulation, distance estimates between anchor sources and binaural microphones are obtained from positions of cross-correlation maxima, which further yield the desired head coordinates. A particularly attractive case is to use high carrier frequencies where disturbing environment noise is lower and sensitivity of hearing to detect annoying anchor sources is also lower.