[LEAPSECS] multiple UTCs

[Tom Van Baak]

> Because access to UT1 requires frequent network access.  I'm thinking

> about atomic clocks that sit on a shelf for years, or which will be used

> in isolated locations.  We've discussed the use cases (for longer lead

> time on leap seconds) in previous threads.


On network -- are there any earth orientation sites that are
not on the internet yet? Even copper or sat-phone dial-up
once a day or week would give UT1 to many decimal places.

On atomic clocks -- I happen to have quite a few of them on
shelves here. It turns out when you power them up, they don't
know what time it is -- so you have to set them to something.
You need communication with the outside world for this.


> Even here there are multiple tradeoffs available, when realising UT1 by

> atomic clock plus predicted offset.  If you retrieve Bulletin A weekly

> then you get a tracking precision on the order of 1 ms.  It looks like

> if you examined the daily data, making much shorter-range projections,

> you could get a tracking precision more like 100 us.  How network-reliant

> are you willing to be, and how close to UT1 do you need to be?


I agree with the tradeoff assessment. I'm just confused about
where on earth you are talking about. Even while trekking in
Nepal I could get you DUT1 if you needed it. I've heard the
south pole also has internet. What sort of expensive telescope
is so far away that it can't get UT1? If so, how is it monitored
or how does it send data back to civilization?

/tvb