[LEAPSECS] UT1 via NTP

[Rob Seaman]

One uses the tools as designed for diverse purposes. NTP in a pool
environment is accurate to a few milliseconds. With our local GNSS
references something better than a millisecond. With an IRIG shared
memory reference maybe an order of magnitude better. Hardware time
capture for our Meinberg IRIG PCIe cards is spec'ed and measured to 5
microseconds. The PTP versions of those cards quotes something better
than 1 microsecond. Hardware time capture to OCXO in the Meinberg M1000
should be precise / accurate to 100 nanoseconds. All of these are
commercially available with only ordinary attention to metrology, e.g.,
like understanding the calibration of a precision balance in a lab.
Meinberg has an excellent monitoring tool built in to their reference
clocks.

"Customers" (internal or external) for astronomical timekeeping (but
should be applicable to other fields) may require TAI, GPS, UTC, UT1, or
more esoteric things like TT. I can set the Meinberg references to
deliver all of these except UT1. All the rest would follow. I'd be happy
to hear about support from other vendors. Needless to say, commercial
timekeeping vendors should also be expected to implement conforming leap
second support for their internet attached devices.

Rob

--


On 3/19/18 12:41 PM, Hal Murray wrote:
>> The issue has come up now since a colleague asked about best practices for
>> access to UT1. In the mean time he's implemented yet another internet
>> retrieval of Bulletin A. Perhaps it needs to be stressed again, astronomers
>> require access to both Universal Time and Atomic Time. 
> What level of accuracy are you interested in?
>
> NTP is unlikely to provide good results if there is only one server and there 
> isn't a good network connection to it.
>
> Perhaps we should setup a simple UDP server that responds with the UT1-UTC 
> offset.  The idea is that you can get a good UTC via GPS or good local NTP 
> servers.
>
>

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