Re: [LEAPSECS] Precise time over time

From: Ed Davies <>
Date: Fri, 12 Aug 2005 14:20:54 +0100

Poul-Henning Kamp wrote:
> In message <>, Greg Hennessy writes:
>>On Fri, 2005-08-12 at 08:44 +0200, Poul-Henning Kamp wrote:
>>>In message <>, Greg Hennessy writes:
>>>>>Will you support a proposal that keeps leap-second (or -minutes),
>>>>>but mandates that they be determined 40 or 50 years in advance ?
>>>>Determined to what accuracy?
>>>Whatever the prediction is able to nail it to.
>>>I realize that this means that the bounds on |UT1-UTC| increases
>>>to about a minute, worst case, but already given todays predictive
>>>capabilities, I think it will be possible to keep the difference
>>>within a handful of seconds.
>>I personally would NOT support such a proposal then.
>>I might be willing to support a proposal that calls for broadcast of the
>>difference of UT1-UTC as well of a long term determination of leap
> I took for granted that the UT1-UTC difference needs to be made
> electronically available.

Currently UT1-UTC is made available on the broadcast time
signals (WWV, Rugby, etc) to a resolution of 0.1 seconds.
The encoding assumes |UT1-UTC| < 0.9 seconds.

Anybody have any idea how many systems actually make use
of this? How this signal deals with the difference going
over 0.9 second is, I think, a relatively minor point but
it does need to be considered.

Ed Davies.
Received on Fri Aug 12 2005 - 06:21:20 PDT

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