Hi, On 2020-03-09 22:31, Poul-Henning Kamp wrote: > -------- > In message <[email protected]>, Attila Kinali > writes: >> On Mon, 09 Mar 2020 13:44:59 +0000 >> "Poul-Henning Kamp" <[email protected]> wrote: >> >>> I'm thinking 24h (to minimize GPS periodicities) frequency measurement >>> and adjustment, with a continuous very weak proportional phase adjustment >>> to come with measurement noise and rounding errors ? >> Please correct me if I'm wrong, but that sounds like a >> simplified version of a Kalman filter, with the only >> predicted variable being the frequency of the LO. > I think this has many names. > > Dave Mills called it a FLL - Frequency Locked Loop. > > I'm not sure a Kalman filter would really do much extra for the > basic GPS+(OCXO|RB) case, unless you get advanced and also feed it > temperature and air pressure. > > Once you have more than two references, Kalman makes a lot of sense. > > The Kalman filter has the benefit of auto-tuning on itself as you run-in, but for a time-frequency system, it's just a self-tuning PI-loop, so when it have stabilized, the difference is very small. It took a bit of re-drawing of the processing, but when it showed up on the sketch-book it was very clear what was going on.
Cheers, Magnus _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
