Some are and some aren’t. Last year, Alien Technology introduced its Intelligent Tag Radar, which enables users to determine the direction, distance and speed of an EPC Gen 2 UHF passive tag. Alien previewed this software at RFID Journal LIVE! 2008 (see Alien Software Adds Context to Tag Reads). Impinj added a similar feature to its Speedway interrogator in October 2007 by offering a free upgrade to its Octane firmware (see RFID Interrogators Grow Up).
Even if you don’t own one of these readers, companies have developed systems for determining directionality. One option is to have one antenna placed ten feet in front of the dock door, and another placed at the dock-door opening. If the tag is read by the antenna at the opening before it is read by the one ten feet inside the building, the pallet is determined to be arriving, and if the read sequence is reversed, the pallet is deemed as being shipped. Some companies have also used electric eyes to determine the direction a product is moving, but this adds to the cost of the system and installation.
—Mark Roberti, Editor, RFID Journal
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