Re: [LEAPSECS] A lurker surfaces

From: Zefram <zefram_at_FYSH.ORG>
Date: Wed, 3 Jan 2007 10:05:27 +0000

Magnus Danielson wrote:
>TA(GPS) = GPS + 19 + C0

No, there is no TA(GPS). TA(k) are distinct timescales that AFAICT
generally do not attempt to track TAI. Presumably they are intended as
maximally stable frequency standards, not steering to maintain long-term
interval accuracy, like TAI itself.

>[UTC-GPS time] = -14 s + C0, [TAI-GPS time] = 19 s + C0, global uncertainty is of order 10 ns.

The formula implied by this is

        TAI = GPS + 19 s + C0

which can be readily rewritten as

        TAI(GPS) = GPS + 19 s
        TAI = TAI(GPS) + C0

the latter half of which is how the rest of Circular T works. They
actually describe the corrections as "UTC - UTC(k)", but of course that's
the same thing as TAI - TAI(k).

-zefram
Received on Wed Jan 03 2007 - 02:06:44 PST