Re: [LEAPSECS] Equitable estoppel

From: Tom Van Baak <tvb_at_LEAPSECOND.COM>
Date: Mon, 18 Dec 2006 23:46:17 -0800

> So they effectively create a new time scale which began 2000-01-01,
> which increments with magical SI seconds that presumably are intended
> to have the same length as those in the TT coordinate frame, which is
> presumably intended only to be valid within geostationary orbit
> (Mondiale), yet which is intended to be valid for the next 32800 years.
> It is apparently motivated by UTC and TAI and GPS time, but not
> explicitly based on them.

Perhaps a little off-topic and I'm not sure if anyone
mentioned this yet but several of us heard at PTTI
a few weeks ago that Galileo has decided to use the
same epoch as GPS for their internal, continuous,
non-leap time scale

I didn't check the ICD but I assume this is partly to be
compatible with existing satellite timing applications
and partly to avoid polluting the otherwise well-defined
meaning of TAI -- the paper clock upon which UTC is
based to which the national realtime UTC(k) are steered.

So this is good news - at least it's one example where
a perfectly good timescale is not destroyed by usurping
its name for another purpose.

/tvb
Received on Mon Dec 18 2006 - 23:46:47 PST