A novell wireless forklift positioning system for indoor and outdoor use

Precise tracking of industrial transportation means - e.g. automatic guided vehicles, cranes, forklifts, etc. - is becoming increasingly important for optimizing logistics processes and storage management. Real time forklift tracking can supplement or replace RFID systems in applications where flexible storage is wanted, where real time information is needed or when item tagging is inappropriate due to costs or physical constrains. In this paper a high performance 5.8 GHz wireless forklift positioning system is introduced. Round-trip time-of-flight (RTOF) measurements provide a set of ID distance values between an arbitrary number of mobile and fixed secondary radar units attached to the forklift and to the infrastructure, respectively. With an optimized geometry based heuristic localization method the position and orientation of the forklift is derived. The proposed method can deal with faulty RTOF measurements, e.g. due to multipath distortions, and it enables a robust and reliable localization. The proposed RTOF system concept allows a minimal complexity of the infrastructure since no backbone network and no dedicated synchronization scheme is needed. An indoor test campaign with a forklift in a steel mill proved a measurement uncertainty of position and orientation below plusmn5 cm and plusmn10deg, respectively, even without the use of any assisting inertial or dead reckoning sensors. This outstanding performance makes the system ideally suited for various applications in production, logistics and storage.