A system for estimating motion parameters corresponding to a user. The system may generally include a receiver operable to receive a signal from an external source, an inertial sensor operable to be coupled with the user and arbitrarily oriented relative to the direction of user motion for generation...http://www.google.de/patents/US7827000?utm_source=gb-gplus-sharePatent US7827000 - Method and apparatus for estimating a motion parameter
