IERS Message No. 40 -- February 13, 2003: Colloquium on the UTC Timescale

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Sam Wormley

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Feb 13, 2003, 10:15:40 AM2/13/03
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IERS Message No. 40 February 13, 2003
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Colloquium on the UTC Timescale

28-30 May 2003, Torino (Italy)

Istituto Elettrotecnico Nazionale "Galileo Ferraris"
Conference Hall, Strada delle Cacce, 91, Torino (Italy)


Preliminary Announcement

A Colloquium on the UTC Timescale will be held at Istituto
Elettrotecnico Nazionale Galileo Ferraris (IEN) in Torino, Italy from
28-30 May 2003. The purpose of the colloquium is to discuss the future
of the UTC timescale.

As a result of issues raised by sector members of the ITU-R
(International Telecommunication Union - Radiocommunications) and a
letter from the Director of the Bureau International des Poids et
Mesures (BIPM) to the Secretary General of the ITU, a new question,
ITU-R 236/7 (2000) "The Future of the UTC Timescale", was generated by
ITU-R Study Group 7 (Science Services) Working Party 7A (Standard
Frequency and Time Signal Services). The question considers the future
definition and use of Coordinated Universal Time (UTC) in the ITU-R
Recommendations.

Any major change to the UTC timescale as defined in the current
recommendations has a potentially significant impact on synchronization
of communications networks and navigation systems and time distribution
performance. Accordingly, Study Group 7 Working Party 7A has established
a Special Rapporteur Group (SRG) to specifically address the future of
the leap second and related issues.

The SRG has held several coordination and technical exchange meetings to
generate, analyze and discuss alternative approaches to reduce or
eliminate the operational impact of the leap second. The work to date
has produced a consensual opinion that the SRG wants to present and
discuss with interested and representative parties. In support of that
purpose the SRG has organized a concluding Colloquium for deliberating
and drafting a recommendation to the ITU-R.

Invited presentations will be made by distinguished representatives in
the areas of International Timekeeping, Navigation, Earth Rotation,
Telecommunications and Internet Timing. These areas could be impacted by
changes in the UTC Time Scale. In addition, contributed presentations
will be sought to insure that additional viewpoints would be expressed.

Additional information can be obtained from Ron Beard, Chairperson of
the SRG (Ronald...@nrl.navy.mil) and Bill Klepczynski, Secretary of
the SRG (wkle...@comcast.net).


General information

Technical Program:

Ron Beard, Chairperson of the SRG
E-mail: Ronald...@nrl.navy.mil

Bill Klepczynski, Secretary of the SRG
E-mail: wkle...@comcast.net

Local Organizing Contact Person:

Elisabetta Melli
Istituto Elettrotecnico Nazionale "Galileo Ferraris"
Strada delle Cacce, 91 - 10135 Torino
E-mail: me...@amm.ien.it


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eawck...@yahoo.com

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Feb 13, 2003, 4:04:06 PM2/13/03
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Sam Wormley <swor...@mchsi.com> wrote:

> The SRG has held several coordination and technical exchange meetings to
> generate, analyze and discuss alternative approaches to reduce or
> eliminate the operational impact of the leap second.

The "operational impact" is a result of foggy thinking by people who
ought to know better: UTC is not a time-scale, it is a _calendar_.
People who use it as a time-scale (interval timing, etc) get precisely
what they deserve.

Tim Hogard

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Feb 13, 2003, 5:32:52 PM2/13/03
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eawck...@yahoo.com wrote:
The real problem is that any real time keeping quickly goes into
the too had basket within seconds of learning the truth about time
vs the calendar. The result is they are set as equal. Its like a
converstation I was having about one my computer clocks the other
day. I said it was fast and the other person couldn't understand
how a fast clock was behind since the common use of the concept of
a fast clock is ahead but thats just another twist to the precision
vs accuracy discussion. a fast colck a day it gets resetclocks th

The GPS system fixed the problem by using fixed length seconds and
will always use them. Galileo in theory could do something else.

One issue for the SRG is that many that need critical timing to
work properly assume that a second is exactly a second long and
that there will be a interger number of them in a day. I'm not
sure what the timing comittee wants to do but I expect it has
something to do with the oddness of adding a leap second at the end
of June (is there still on going to be added then?)

I think the operational impact will be that people using GPS for a
time source will keep getting their integer seconds defined by
9,192,631,770 ticks of the cesium atom and the astronomers will
argue about using 9,192,631,770.0000000211 tocks per day till
they can come up with a cleaner model. Aren't the good clocks only
good for about 17 to 19 digits.

Things are going to get real screwy if they start messing with the
GPS time signal. Its bad enough when 23:59:60 shows up on a clock.
Most radio systems that use GPS for a time base for synchronization
just want to know when the second starts. If thats going to drift
much, they have to reallocate time slots and they tend to be set
on about 50ns windows. A GPS reciver will know its time to within
about 9 ns to work properly. Any change smaller than 1/100th of
that should get lost in the DPLL so it may not matter much.

-tim
http://web.abnormal.com

Spaceman

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Feb 13, 2003, 5:37:41 PM2/13/03
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"Tim Hogard" <tho...@abnormal.com> wrote in message news:b2h6ek$291d$1...@knotty.abnormal.com...

> eawck...@yahoo.com wrote:
> The GPS system fixed the problem by using fixed length seconds and
> will always use them.

Fixed length seconds?
<ROFLOL>

Shit you guys are so freakin lost!

seconds do nto have lengths" at all

GPS works because it "syncronizes" the clocks.
That is all it need do to find
"absolute positions"
by simply using "absolute same times"

time units "are not" distances.
distances are not time units.
sheesh!

Freakin foolish time travel dorks have invaded
the school system!
<LOL>


Sam Wormley

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Feb 13, 2003, 5:42:18 PM2/13/03
to
Spaceman wrote:
>
> Fixed length seconds?
> <ROFLOL>
>
> Shit you guys are so freakin lost!
>

+------------+
| PLEASE |
| DO NOT |
| FEED |
| DA |
| TROLLS |
+------------+
| |
| |
`\ '/ / ' /

Spaceman

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Feb 13, 2003, 5:46:50 PM2/13/03
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Sam,
your trolling me with the troll sign is pretty sad.
Seek a life you time travel dork.


"Sam Wormley" <swor...@mchsi.com> wrote in message news:3E4C1F48...@mchsi.com...

Andrew Knox

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Feb 15, 2003, 4:47:45 PM2/15/03
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I don't see any problem with UTC, but as I expect we are talking about the
measurement of time it should be variable and based on an update of UT2! The
sync'ers can use one of the other definitions as a frequency reference with
phase information if needed such as TAI.

Regards
Andrew

<eawck...@yahoo.com> wrote in message
news:d3c57e81.0302...@posting.google.com...

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