This technique uses passive UHF RFID tags that are fixed to the objects that have to be located. The area where locating has to be done is equipped with a number of antennas connected to RFID readers. The antennas constantly send signals and receive a response as soon as a RFID tag comes into the reading area of an antenna. When RFID tags move in the area the location is updated as soon as another antenna “sees” a new RFID tag. The technique for this case is the so called “presence detection”.
This technique uses passive UHF RFID tags that are fixed to the objects that have to be located. The area where locating has to be done is equipped with one central antenna “STAR” and a number of E- nodes. The E-nodes create an interrogation space and as soon as a RFID tag enters an interrogation space the information is send to the STAR and the RFID tag is located. Advantage of this solution is that objects not necessarely have to move to become visible as they are interrogated via the E-nodes
Vision Based Locating
This technique is vision based and makes use of barcodes for localisation. Load identification can either be done manually or via Barcode or RFID scanning. The area where locating has to be done is equipped with a grid of 2D barcodes mounted to the ceiling of the building. Lift trucks have to be equipped with a camera on the roof for locating and a set of sensors on the fork to identify the load and eventually the height. When the lift truck picks a load it is determined by the sensors on the fork, the camera on the roof determines the route and final location, as soon as the load is dropped off the last location is stored for the load. (presentation)
This technique is especially applicable for warehouses with racked storage facilities, roll handling operations and handling of products which are difficult to label.