Abstract: Aspects of the present invention relate to systems, methods, and computer program products for tracking an orientation of a first object. The system includes a light emitting device located relative to a second object at a fixed predetermined position; a sensor having a photodetector array that is configured to receive incident light emitted from the light emitting device, the photodetector array being mounted on the first object; and a processor coupled to the photodetector array, the processor configured to determine the orientation of the first object relative to the second object based on an angle of incident light detected by the photodetector array from the light emitting device.

Abstract: Among other things, positioning a magnetic instrument on a pedestrian; positioning an inertial instrument on a foot of a pedestrian; receiving positioning signals at the pedestrian; aligning the inertial instrument based in part on the received positioning signals; calibrating the magnetic instrument using the inertial instrument; and tracking the pedestrian using the calibrated magnetic instrument and the inertial instrument.

Abstract: An apparatus for measuring an inertial property on a set of one or more axes is disclosed. The apparatus includes a first inertial sensor arranged to measure the inertial property, having a first predetermined resolution and a first predetermined measurement range, and a second inertial sensor arranged to measure the inertial property, having a second predetermined resolution and a second predetermined measurement range. The second resolution is coarser than the first and the second measurement range is larger than the first. A processing system is adapted to receive measurement signals from the first and second inertial sensors and, when the output of the first inertial sensor is within the first predetermined measurement range, to update an error estimate for adjusting the output of the second inertial sensor, based on the measurement signals from the first and second inertial sensors.

Abstract: Systems and methods for tracking the motion of a game controller and a player's body part are disclosed. The method includes receiving a video signal from a webcam, generating movement data corresponding to the motion of the game controller, tracking first predetermined degrees of freedom of motion of the body part, generating feature location data based on a location of at least one identifiable visual feature of the game controller, and estimating second predetermined degrees of freedom of a motion of the game controller.

Abstract: Among other things, first data is received from an inertial tracking device worn by a first person, the first data approximating locations along a first path that was traversed by the first person. Second data is received from an inertial tracking device worn by a second person, the second data approximating locations along a second path, similar to the first path, that is being traversed by the second person. A determination is made about how to guide the second person to reach the first person by using the first data and the second data to correlate locations along the first path and corresponding locations along the second path.