A global radionavigation system that enables user with special receivers to obtain position information by measuring phase difference between precisely timed signals radiated by a network of eight transmitting stations deployed worldwide. Note: The transmitted signals time-share transmission on frequencies of 10. 2, 11. 05, 11. 33, and 13. 6 kHz. Since the transmissions are coordinated with UTC (USNO,) they also provide time reference.