Tracking human movements and locomotion accurately in real time -e.g. for providing real walking in virtual environments -requires expensive tracking systems which need a lot of time to install. Furthermore, the costs typically increase with the size of the tracked space as these systems rely on external references. This poster presents an approach to significantly reduce costs for tracking human locomotion in large, potentially unlimited tracking spaces.The proposed approach employs a low-cost user-worn position and orientation tracking system to track the position and orientation of limbs including the user's feet. To associate the relative limbs' movement within the user's local coordinate system with the absolute movement in a given environment, the feet stance phase is used. Whenever a foot enters the stance phase, the local position is locked onto the global position because the foot is not moving. This allows tracking a person with all locally tracked objects -e.g. limbs, head, etc. -by temporarily locking the absolute position alternately to the user's feet in a step by step manner. This tracking works continuously and in real time without any external references.