The ultra-wideband (UWB) RFID system, supplied by Zebra Technologies, includes RFID tags embedded in between the two layers of plastic that make up a player’s shoulder pads, as well as tags in referees’ back pockets, tags on the tops of the chains used to mark yardage, and receivers affixed to the ribbon infrastructures at the stadiums, separating the lower and upper tiers and typically holding video boards. Zebra’s MotionWorks sports solution can identify the locations of players and equipment within 6 inches. The tags pulse a 6.35 GHz to 6.75 GHz UWB signal approximately 25 times per second, and have a read range of up to about 325 feet. Each tag’s battery has a lifespan of approximately seven years.
Additional Soure: http://www.zebra.com/us/en/nfl.html