Abstract: An autonomous system of at least four transceivers located at fixed positions on a campus are networked to each other. Persons on the campus carries a fob or other transmitter. Each transceiver has a clock synchronized in time by a GPS satellite time signal. A location processor knows the fixed locations of the transceivers. When activated, each fob (of unknown location) transmits a unique alert signal. Each transceiver receives the alert signal. Based on time of receipt and known information, the location processor calculates a distance relative to each transceiver at which the fob is located to determine the location of the fob.