[time-nuts] HP 523B frequency counter & Sputnik

Tom Van Baak tvb at LeapSecond.com
Thu Oct 4 16:37:03 EDT 2007

> Is this a typo on the Ashby-Relativity.htm web page?
> "At present one cannot easily perform tests of relativity with the system 
> because the SV clocks are actively steered to be within 1 microsecond of 
> Universal Coordinated Time (USNO)."


I think it may be more dated than a typo. It's possible that
early accuracy targets for GPS were just 1 us, with heavier
steering. Now, as you know, it's down to ns short-term and
tens of ns of UTC long-term.

For a more detailed work by Ashby, see:



More information about the time-nuts mailing list