What type of RFID system can interrogate tags from that distance?
There are, to my knowledge, no RFID systems that work consistently at a distance of more than 1 kilometer (0.6 mile). Most active RFID systems have a read range of about 100 meters (328 feet). Systems optimized for longer read ranges can push that out to 500 meters (1,640 feet), and there might be systems that can, on occasion, read tags from much farther away—but in general, companies looking to locate objects over such long distances tend to use RFID transponders combined with GPS or GPRS technologies.
—Mark Roberti, Founder and Editor, RFID Journal
Previous Post How Would I Set Up a Lap-Counting System With RFID Tags for Each Competitor? »