A locating and tracking system is provided in which the assets are desired to be located and tracked are associated with either radio frequency (RF) tags or radio frequency identification and radio frequency data communication (RFID/RFDC) devices. Depending on which device is attached to the asset, the...http://www.google.de/patents/US7084740?utm_source=gb-gplus-sharePatent US7084740 - Wireless locating and tracking systems
