[LEAPSECS] yet another satellite time scale

Steve Allen sla at ucolick.org
Thu Oct 8 03:46:53 EDT 2009

Within the recent CGSIC proceedings is the overview presentation by
Lewandowski of the BIPM.
It includes one page plotting the various satellite time scales and
another showing the Tower of Babel.

With gratitude toward that presentation and the Peoples Republic of
China I have enhanced my web pages to include Compass or BeiDou System
Time (BST) as one of what are now three discernibly distinct broadcast
time scales for navigation which run parallel to the original
Ephemeris/Terrestrial Time.
This plot is, of course, not making it clear that GPS time and Galileo
System time (and perhaps others yet to come) are (at nanosecond
precision) not actually the same time scale.

In the light of all this I find myself ever more confused by the
assertion that "only UTC can be disseminated". Plainly there are lots
of time scales being broadcast, and according to the BIPM Circular T
some of the ones named UTC(k) are less stable than ones not named UTC.

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

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