Inertial sensor data correction

Abstract

A method is provided for determining corrections to rate data output by inertial sensors of a type typically used in tracking changes in orientation of an object. The present invention also extends to a tracker system incorporating the correction functionality of the present invention. The method makes use of rate data output by inertial sensors associated with the object being tracked and rate data derived from measures of orientation supplied by a non-inertial tracker system also associated with the object being tracked and comprises determining from those rate data corrections for errors due to misalignment in rate data output by inertial sensors, by calculating a mapping between vectors linking points in inertial sensor rate space represented by a sample set of received rate data from the inertial sensors and vectors linking points in a derived object orientation rate space represented by a corresponding and synchronised sample set of derived rate data. Corrections for inertial sensor bias may be determined separately from corrections for misalignment-related errors, after correction of inertial sensor rate data for misalignment-related errors by determining the vector translation between a point represented by corrected inertial sensor rate data in the derived object orientation rate space and the point in the same rate space represented by derived rate data synchronised therewith.