M. Warner Losh wrote:
> : > If DUT1 is broadcast, then one can set the time keeping device to UT1
> : > by a means similar to setting it to UTC, even if DUT1 exceeds 0.9s
> : > with a similar accuacy (or better). There's nothing that says a watch
> : > has to display UTC to be set correctly.
You seem to expect celestial navigators to become more sophisticated in
these matters of time scales than is presently the case. It would be far
better, in my option, not to tinker with the definition of UTC and of
civil time at all, but leave civil time zones tied approximately to UT1.
"There's nothing that says a watch has to display UTC to be set
correctly." But then the user would have to carry two watches, one set
to an approximation of UT1 (e.g., UTC + DUT1) and another set to civil
time (TI, or local zone time, or whatever). For simpler, it would be,
with far less impact on ordinary users of time, not to let UTC (or its
replacement) differ from UT1 by more than the present +/- 0.9 s.
UTC is not broken. There is no need to "fix" it.
> I'd also add that GPS receivers today already do exactly this sort of
> correction when they decode the GPS time, but display the UTC time.
>
True. But GPS receivers are electrically powered, and are not a fallback
for the case when a boat's electrical systems fail. Nor are they a
backup system for the case when the the boater is in proximity to a
war zone where the U.S. DoD is jamming or degrading the civil SPS GPS
service.
--
James Maynard
Salem, Oregon, USA
Received on Fri Jan 20 2006 - 21:52:40 PST