Re: [LEAPSECS] prep for WRC 23
On 2023-12-22 22:35, Seaman, Robert Lewis - (rseaman) wrote: E pur si muove Natura non facit saltus -- why should UTC? UTC may no longer serve as a kind of solar time (after 2026 or 2035, or somebody said 2040 the other day), but civil time will continue to have engineering requirements tracing to both solar and atomic time scales. As far as required by local civil time scales, continuous UTC can stand for solar time (UT1 up to 15 min) for several centuries. Current positioning applications on the surface of the Earth cannot be performed without knowledge of UT1 up several milliseconds. These applications work in wrist watches today and they do not need nor exploit the leap seconds of UTC. What type of engineering requirements can be satisfied with the current UTC with leap seconds that fail when UTC becomes continuous? The Russians have required more time for updates in satellite software, they have not said that it cannot be done. Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
On Sat, Dec 23, 2023, 12:02 PM Poul-Henning Kamp wrote: > Michael Deckers via LEAPSECS writes: > > >> My Tl;dr version of the resolution is: > > > >> . Please keep DUT1 less than 100 seconds. > > > k) that the maximum value for the difference between UT1 and UTC > > should be no less > > than 100 seconds, taking into account the constraints of the > > technological systems > > expected to be used to disseminate this value, " > > You're right, I misread that. > > They /really/ dont want to ever see a leapsecond or leapminute, do they ? > I'd love for them to have 6 digits for the offset.. .99. Iirc prior discussions that puts us 6000 years or so in the future. 6000 years ago we were just inventing writing, just domesticated plants and food animals and were just starting to forge metal on a vast scale... 100s gives us until at least 2150 in all likelihood (exactly date might be 2100 or 2200 though). So year... safely dead before any of these dates... Warner Ps all my examples are +/- maybe 1000 years and you can rightly quibble with them... but it wouldn't change the main point. :). -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > ___ > LEAPSECS mailing list > LEAPSECS@leapsecond.com > https://pairlist6.pair.net/mailman/listinfo/leapsecs > ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
Michael Deckers via LEAPSECS writes: >> My Tl;dr version of the resolution is: > >> . Please keep DUT1 less than 100 seconds. > k) that the maximum value for the difference between UT1 and UTC > should be no less > than 100 seconds, taking into account the constraints of the > technological systems > expected to be used to disseminate this value, " You're right, I misread that. They /really/ dont want to ever see a leapsecond or leapminute, do they ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
E pur si muove UTC may no longer serve as a kind of solar time (after 2026 or 2035, or somebody said 2040 the other day), but civil time will continue to have engineering requirements tracing to both solar and atomic time scales. Shenanigans will result, bedeviling future blinkered technocrats. Rob Seaman Lunar and Planetary Laboratory University of Arizona On 12/22/23, 12:42 PM, "LEAPSECS" wrote: Resolution 655 was approved by the WRC plenary, reportedly in a very routine manner and with with neither drama nor long speeches. The full text of the resolution is on page 399 of the provisional final acts: https://www.itu.int/dms_pub/itu-r/opb/act/R-ACT-WRC.15-2023-PDF-E.pdf My Tl;dr version of the resolution is: Timescales are not spectrum regulation, we defer to CPGM and BIPM on that, but will handle any fall-out as far as radio signals go. Please keep DUT1 less than 100 seconds. Then BIPM then issued this press release: https://www.bipm.org/en/-/2023-12-12-wrc-dubai Which I read as death notice for the leap-second, with further details of the funeral to announced after CPGM's meeting in 2026. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
On 2023-12-21 18:22, Poul-Henning Kamp wrote: My Tl;dr version of the resolution is: . Please keep DUT1 less than 100 seconds. I do not read that from the text. The original [page 399] says: " recognizing . k) that the maximum value for the difference between UT1 and UTC should be no less than 100 seconds, taking into account the constraints of the technological systems expected to be used to disseminate this value, " This seems to say that on the contrary, at least 3 decimal digits will be needed for the integral part of the approximation of |UT1 - UTC| in time signals that include an estimate of UT1 - UTC after 2035. Anyway, I do not think that the CIPM will recommend a maximal value of 100 s for |UT1 - UTC| because there is a slim chance that this will not be enough until 2135. On the other hand, ITU-R might come up with a scheme where the approximation of (UT1 - UTC) is only given modulo 100 s in radio signals, so that 2 digits would suffice for the integral part. Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
Resolution 655 was approved by the WRC plenary, reportedly in a very routine manner and with with neither drama nor long speeches. The full text of the resolution is on page 399 of the provisional final acts: https://www.itu.int/dms_pub/itu-r/opb/act/R-ACT-WRC.15-2023-PDF-E.pdf My Tl;dr version of the resolution is: Timescales are not spectrum regulation, we defer to CPGM and BIPM on that, but will handle any fall-out as far as radio signals go. Please keep DUT1 less than 100 seconds. Then BIPM then issued this press release: https://www.bipm.org/en/-/2023-12-12-wrc-dubai Which I read as death notice for the leap-second, with further details of the funeral to announced after CPGM's meeting in 2026. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
On 2023-11-26 06:59, Steve Allen wrote: This week began the meeting of ITU-R WRC 23. ..and it ended on 2023-12-15. The ITU-R news channel [https://www.itu.int/en/mediacentre/Pages/PR-2023-12-15-WRC23-closing-ceremony.aspx] mentions a "key outcome"of WRC23: " ∙ Endorsement of the decision by the International Bureau of Weights and Measures (BIPM) to adopt Coordinated Universal Time (UTC) as the de facto time standard by 2035, with the possibility to extend the deadline to 2040 in cases where existing equipment cannot be replaced earlier. " It is unclear what this is intended to mean: endorsement of the CGPM (not BIPM) decision implies that UTC will be continuous (not "de facto standard") from 2035 onward, so what "deadline" may still be shifted to 2040? ITU-R continue their (and CCIR's) tradition of murky statements about UTC. Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
On 2023-11-26 06:59, Steve Allen wrote: This week began the meeting of ITU-R WRC 23. After closure of work related to resolution 655 of WRC 2015 at the World Radio Conference 2023 in Dubai, the BIPM has added the web page [https://www.bipm.org/en/-/2023-12-12-wrc-dubai] One particular technical aspect is mentioned on this page: some lead time is required to adapt the (few) radio time signals that disseminate the approximation DUT1 of UT1 - UTC to the larger range of |UT1 - UTC| that will be allowed after 2035. This is worded quite implicitly, so that one cannot be sure ∙ whether there will still be an official approximation of of UT1 - UTC after 2035, similar to the one currently produced by the IERS with Bulletin D; ∙ if, yes, what the resolution and the range of that approximation would be. The CIPM will certainly try to avoid to introduce an official approximation of UT1 - UTC with a resolution of whole seconds and whose values change only at the end of a UTC month. Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
On 2023-11-26 17:38, Michael Deckers wrote: online at [https://www.itu.int/oth/R0A0807/en] when he meant: nline at [https://www.itu.int/pub/publications.aspx?lang=en=R-REP-TF.2511-2022] Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] prep for WRC 23
On 2023-11-26 06:59, Steve Allen wrote: This week began the meeting of ITU-R WRC 23. One preparation for this meeting was a document issued early this year The future of Coordinated Universal Time https://www.itu.int/en/itunews/Documents/2023/2023-02/2023_ITUNews02-en.pdf This looks at the use of time in several arenas, many of which would like UTC to stop having leap seconds. The result of resolution 655 of WRC 2015 is ITU-R document TF 2511-0, online at [https://www.itu.int/oth/R0A0807/en]. It gives an overview of how users of UTC are affected by the current (discontinuous) form of UTC and by the proposed continuous form; it was written before the CGPM decision of 2022 on the change in UTC. Many also allow that keeping agreement with the earth in the long run is necessary, and that they have no idea how to do that. A working group of the CCTF has since been charged with developing (among other, more important things) a proposal for measures to constrain |UT1 - UTC| after the new bound is reached. Since such measures would only apply in over 100 years, when the requirements for a reference time scale cannot reliably be predicted, anything beyond a necessarily incomplete list of possibilities (a discontinuous step, change in the rate d(UTC)/d(TT), using predictions of UT1 - UTC, etc) would be wasted effort. Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
