Tracking of transport vehicles for warehouse management using a wireless sensor network

A warehouse management system is a key part of the supply chain and controls the movement of goods within a warehouse. Usually the state of a warehouse is managed in a central database, which must be updated for every storage and retrieval activity. The entire process is prone to errors, because it relies on manual activities performed by employees. This paper presents a technique to monitor the manual transportation processes of goods in a warehouse, in order to update the database automatically. In the proposed scenario, transport vehicles such as forklift trucks or pallet jacks are equipped with wireless sensor nodes and every storage and retrieval activity is reported to the warehouse management system. Tracking of transport vehicles is performed with nanoLOC sensor nodes, which offer range measurement capabilities. This radio positioning system determines the range between two devices by measuring the signal propagation delay. The paper describes the tracking of transport vehicles with range measurements and trilateration using the Extended Kalman Filter. It presents experimental results of tracking a forklift truck in a warehouse.