[LEAPSECS] leapseconds, converting between GPS time (week, second) and UTC

Steve Allen sla at ucolick.org
Wed Jan 16 04:35:15 EST 2019


On Wed 2019-01-16T00:00:55-0800 Paul Hirose hath writ:
> The "rubber second" era is supported. That accounted for about 90% of the
> workload to create the UTC implementation!

Does it know that rubber seconds do not apply to timestamps in central
Europe made using DCF77 from 1970-01-01 to 1972-01-01?

After the CGPM redefined the SI second in terms of cesium the German
time service bureau determined that they could not use the old scheme
of BIH UT2 with its rubber seconds.  They had convinced themselves
that German law required them to broadcast SI seconds.

So starting 1970-01-01 DCF77 changed to broadcast Stepped Atomic Time
(SAT) with second markers that were 1 SI second apart except on
occasions when they were 1.2 SI seconds apart in order that the time
markers would stay close to UT2.

This was one of the issues of concern in the CCIR preparatory meetings
that led to the decision to have leap seconds.

So they were mostly broadcasting legal SI seconds, but too early in
history to evoke comparisons with "mostly harmless" and "mostly dead".

--
Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat  +36.99855
1156 High Street               Voice: +1 831 459 3046         Lng -122.06015
Santa Cruz, CA 95064           https://www.ucolick.org/~sla/  Hgt +250 m


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