[time-nuts] GPS discipline oscillator vs phase lock

[Attila Kinali]

On Sat, 17 Jun 2017 06:29:02 -0700
jimlux <jimlux at earthlink.net> wrote:

> Well, at JPL we regularly lock two crystal oscillators together that are 
> over a billion km apart with added Allan deviation of less than 1E-15 at 
> 1000 seconds with a radio link at 7.15 GHz.  It's how we measure the 
> distance and velocity to spacecraft (a few cm in range and mm/s in 
> velocity) and from that figure out the gravitational fields (among other 
> things)

This sounds interesing. What do I have to google for to learn more?

			Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson