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GPS-based Products

USNO, as an International GNSS Service (IGS) Analysis Center, provides GPS-based products such as Rapids, Ultras (Ultra-rapids), and UTGPS.  To learn more about how to use these products, click here.


24-hr sets of GPS satellite orbits, satellite- and receiver clock solutions, and earth-orientation parameters. Computed by USNO's IGS Analysis Center every 24 hours.


48-hour sets (24 hours past, 24 hours predicted) of GPS satellite orbits, satellite clock solutions, and earth orientation parameters. Computed by USNO's IGS Analysis Center every six hours.


A GPS-based UT1-like quantity used for extrapolating UT1-UTC past the most recent VLBI measurement. One value per 24 hours; estimated daily.

USNO Master Clock Time
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