Terrain navigation apparatus (1) for a legged animal (2) traversing terrain (3) including a first system (4) for determining position, velocity and heading of the legged animal incorporating sensing means for sensing inertial motion in six degrees of freedom operable to provide signals indicative of...http://www.google.de/patents/US6366855?utm_source=gb-gplus-sharePatent US6366855 - Terrain navigation apparatus for a legged animal traversing terrain
