[LEAPSECS] Ghosts of Leap-seconds past and future

[Richard B. Langley]

I have been asked to remind list members of the presentation by Ron  
Beard, the chairman of ITU-R Working Party 7A, at ION GNSS 2010. The  
PowerPoint slides can be downloaded from here:  
<http://www.navcen.uscg.gov/pdf/cgsicMeetings/50/%5B16%5DITU_Status_UTC_Revision_CGSIC_50th.pdf>.

Here are the conclusions, summary, and actions from the presentation:

CONCLUSIONS

Major scientific and GNSS organizations have not taken issue with the subject
There has been ample opportunity and encouragement to contribute

The lack of response has been interpreted as having no concern and  
thus no established opinion

Little information on quantitative costs has been provided

The few estimates offered seem to be guesses at best

Few observers noted there are costs associated with maintaining the  
status quo that may or may not be mitigated

Most experts in time metrology agree on the necessity for the change  
and offer technical support

The Consultative Committee on Time and Frequency strongly recommends  
proceeding with a decision so enough time is available for any  
necessary software and systems modifications

SUMMARY

Documents demonstrate a clear misunderstanding of the definitions and  
applications of time scales and system times for internal  
synchronization
o Indications that users have the choice between UTC, TAI, UT1, GPS  
Time for their applications is incorrect
o UTC is the only international standard time scale, represented by  
local approximations in time laboratories, that should be used for  
worldwide time coordination and measurement traceability
o TAI is not an option for applications needing a continuous reference  
as it has no means of dissemination, and it is not physically  
represented by clocks
o GPS time is not a reference time scale, it is an internal time for  
GPS system synchronization, as other GNSS system times would be
o A variety of continuous internal system time scales have  
proliferated to provide a solution to the problems associated with  
discontinuities in UTC

The existence of multiple time scales creates potential problems in  
operational use as well as conceptual confusion on the proper  
definition and roles of time references

ACTIONS

Working Party 7A exhausted technical considerations and studies

Consensus not reached on other than technical grounds

Submitted to Study Group 7 for resolution


So far, I have not seen any reports from Study Group 7 subsequent  
deliberations.

-- Richard Langley


Quoting Rob Seaman <seaman at noao.edu>:


> God bless us, every one!

>

> On Dec 26, 2010, at 8:40 PM, Richard B. Langley wrote:

>

>> Quoting Rob Seaman <seaman at noao.edu>:

>>

>>> The ITU, rather, have monomaniacally pursued one-and-only-one  

>>> NON-solution for a decade, and have assiduously avoided  

>>> characterizing the problem they claim to seek to solve.

>>>

>>> "Slander those who tell it ye!  Admit it for your factious  

>>> purposes, and make it worse!  And bide the end!"

>>>

>>> So yes - I will continue to rattle my chains.

>>

>> Dare we hope for a Scrooge-like transformation of the ITU? ;-)

>

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===============================================================================
  Richard B. Langley                            E-mail: lang at unb.ca
  Geodetic Research Laboratory                  Web: http://www.unb.ca/GGE/
  Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506 453-5142
  University of New Brunswick                   Fax:      +1 506 453-4943
  Fredericton, N.B., Canada  E3B 5A3
      Fredericton?  Where's that?  See: http://www.city.fredericton.nb.ca/
===============================================================================