Indoor navigation and vehicle tracking require special measurement techniques. The reference points and routes used by classic AGV (Automated Guided Vehicle) systems are usually buried under floor surface or painted directly on the floor, thus limiting the set of possible transportation paths. However, the indoor environment of an industrial warehouse is dynamic, the number and location of objects inside are subject to frequent changes and these changes might not be reflected in the map of the area. In such conditions, navigation according to the on-board instruments (dead-reckoning) could provide valuable information about the position and orientation of the vehicle. This paper reports test results from a smart sensor using a 6-axis MEMS IMU unit and a self-calibrating procedure for indoor vehicle orientation tracking. The smart sensor, integrated with information from wheel encoders can produce 2D position coordinates suitable for navigation. Original data processing algorithm, applied in the sensor, was developed by the authors as a part of the research project on mobile robotics.