[time-nuts] Synchronisation using GPS

[Shaun Doughty]

Thanks, the VLBI stuff looks pretty relevant and interesting, and I notice
that CNS managed to get an accuracy of a few nanoseconds between receivers
with the M12+'s that Tom mentioned at a 21.5km baseline, which is
encouraging too.

Within the radar network itself we are only really concerned about relative
synchronisation between several sites, but this doesn't seem to be something
that is reported on the majority of receiver data sheets - generally I guess
it's just accuracy to UTC reported, so any information on relative
synchronisation like the CNS tests is pretty useful for deciding whether GPS
is a good idea to replace the current wired system being used as we move to
slightly longer baselengths, and which receiver might be most suitable.

Shaun


----- Original Message ----- 
From: "Magnus Danielson" <cfmd at bredband.net>
To: <time-nuts at febo.com>; <s.doughty at ee.ucl.ac.uk>
Sent: Monday, August 08, 2005 8:02 PM
Subject: Re: [time-nuts] Synchronisation using GPS


> From: "Shaun Doughty" <s.doughty at ee.ucl.ac.uk>
> Subject: [time-nuts] Synchronisation using GPS
> Date: Mon, 8 Aug 2005 13:24:14 +0100
> Message-ID: <005901c59c14$16ec96d0$61292880 at willow>
>
> Shaun,
>
> > Hello, I am currently looking at GPS as a possible way of synchronising
> > transmission/reception within a radar network.  I was wondering if
anyone
> > had perhaps previously used GPS to synchronise various locations in this
way
> > (mine will likely be a couple of km apart max) and if there were any
> > recommended receiver models that might be suitable for this purpose.
>
> The VLBI community excells at this. Look at what they are doing.
>
> > Ideally something approaching differential location accuracy of <1m with
> > synchronisation error between receiver locations of <5ns would be
do-able;
> > has anyone ever undertaken anything similar?
>
> Relative timing like that should certainly be doable using the right
equipment
> and right setup. People that do this uses Geodesic receivers such as
> Ashtech Z12 and a good antenna.
>
> With the relative proximity of only a few km away, the common view aspect
will
> correlate quite well.
>
> Using terms like "common view" and "Ashtech Z12" you will Google yourself
to
> alot of usefull information. You should harvest the archives of NIST, PTTI
etc.
> for good articles on the topic.
>
> This in addition to Toms M12+ links should surely help you to get a better
> understanding.
>
> Cheers,
> Magnus