Direction sensing of moving RFID tags

A system for detecting the direction of movement of an RFID tag along a path comprising two RFID portals, each of said portals being arranged to detect an RFID tag in a respective zone along the path, the zones being arranged to be effectively exclusive of one another, a RFID tag reader having an associated processor and multiple separate ports, each port being connected to one or the other of the portals, the processor being arranged to determine which portal first receives a RFID tag signal or signals and which portal subsequently receives a second signal from the same tag or tags detected by the first signal receiving portal, the processor providing a signal corresponding to a direction of movement, along the path from the first signal receiving portal to the second signal receiving portal.