[time-nuts] Re: Reducing time-interval noise with RNCAN PPP?

[Bill Notfaded]

I'd be interested about GNSS chips that allow external holdover standard?
Like John suggests is this even a thing?

Bill E.

On Sun, Oct 16, 2022, 11:29 AM John Ackermann N8UR via time-nuts <
time-nuts at lists.febo.com> wrote:

> That's an interesting question, and I'm interested in what other might
> have to say.
>
> The first question is, are you thinking of using RTK for real-time
> correction, or post-processing for after-the-fact?
>
> If real-time, you might want to look at Ole Petter Ronningen's work
> about using PPP RTK (not necessarily NRCan) to make an extremely good
> GPSDO -- check out https://www.efos3.com/GPSDO/GPSDO.html (and he has
> some other very informative pages as well.  That project isn't quite
> what you're asking about, but it's close enough to give you some
> starting points.
>
> If post-processing, you can extract clock offset data from the NRCan
> results that will let you see your local clock performance compared to
> the GPS constellation with time lags from a few hours for the
> ultra-rapid corrections to about 17 days for the final corrections.  I
> think the shortest measurement interval that NRCan PPP supports is 30
> seconds.  From what I can determine, the noise floor of the measurements
> is in the mid e-13s at 30 seconds, improving with longer intervals at a
> -1 slope.
>
> If you're brave enough to unsolder the top of the ZED-F9T module, you'll
> find a 64-ish MHz TCXO.  Replacing that with a signal synthesized from a
> better standard might (and I stress "might") provide better short term
> performance.  It's not an experiment I've tried!
>
> John
> ----
>
>
> On 10/16/22 02:55, Marek Doršic via time-nuts wrote:
> > Hi,
> >
> > I am measuring time-interval between Ublox RCB-F9T PPS ouput and another
> clock (e.g. Cs clock), where Ublox is set to time mode with fixed surveyed
> antenna position and data from time-interval counter are corrected for
> quatization error using ublox TIM-TP receiver message.
> >
> > How can results from RNCAN PPP procesing be used to further reduce noise
> in the time-interval data?
> >
> >     .md
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