[time-nuts] SE880 GPSDO

Attila Kinali attila at kinali.ch
Thu Apr 28 19:28:22 EDT 2016


On Fri, 29 Apr 2016 00:35:58 +0200
Ilia Platone <info at iliaplatone.com> wrote:

> The problem is not the absolute stability, but the relative error 
> between the various stations. ie the telescopes clocks must not drift 
> too much by each other.

Unless you want to do online data analysis, this is not really a problem.
The idea is to record all kind of information of the reference oscillator
and the GPS system. Under the assumption that the reference oscillator
frequency is stable enough, you can measure the frequency using GPS
very precisely. You can even factor in some frequency drift (which you
will need unless you let the Rb's run for a couple of hours/days before use).
Or to put it more generally, the more data you have, the more you can
compensate for non-idealities during post-processing.

Yes, you want to achieve absolute timing accuracy, but for that you will
need to start with some stable frequency source, either physical or
virtual, in order to be able to determine time accurately.

At the moment I am just throwing ideas on how to build the system at you.
There are many ways how to build such a system. I somewhat filter on what
I think is a reasonable approach with moderate cost/effort required.
At some point you will need to decide on one or two approaches and calculate
what kind of performance you need from which part to achieve your goal.
Then you will see whether the system can actually work and how much effort
you need to put into the detailed design to get there.

-- 
Reading can seriously damage your ignorance.
		-- unknown


More information about the time-nuts mailing list