Time and Frequency Activities at the U.S. Naval Observatory
NAVAL OBSERVATORY WASHINGTON DC TIME SERVICE DIV
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The U.S. Naval Observatory USNO has provided timing for the Navy since 1830 and, in cooperation with other institutions, has also provided timing for the United States and the international community. Its Master Clock MC is the source of UTC USNO, USNOs realization of Coordinated Universal Time UTC, which has stayed within 5 ns rms of UTC since 1999 and within 3.1 ns rms in 2008. The data used to generate UTC USNO are based upon 70 cesium and 24 hydrogen maser frequency standards in four buildings at two sites. USNO disseminates time via voice, telephone modem, LORAN, Network Time Protocol NTP, GPS, and Two-Way Satellite Time Transfer TWSTT. This paper describes some of the changes being made to meet the future needs for precision, accuracy, and robustness.
- Test Facilities, Equipment and Methods