[time-nuts] The National Labs and the nS.
Mike Fahmie
mpfahmie at lbl.gov
Mon Mar 12 18:35:36 UTC 2007
>
>When you get to the sub-100 ns level UTC is not GPS. And
>UTC(NIST) isn't UTC(USNO). Even the national labs don't
>agree down to the last ns.
>
>/tvb
Remember that no one lab has the true UTC clock. UTC is an offset to Atomic
Time (TAI), and TAI is the weighted average of hundreds of clocks in dozens
of National Labs all over the world. The Bureau International des Poids et
Mesures (BIPM formerly BIH) collects data and publishes TAI, the
International Earth Rotation Service (IERS), determine when Leap Seconds
increment/decrement the offset based on variations of the earths rotational
period.
See: http://www.bipm.fr/en/scientific/tai/tai.html for details!
-Mike-
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