[time-nuts] New Subscriber, DIY GPSDO project (yes, another one)

[Poul-Henning Kamp]

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In message <20200309222553.e5b65b79daa2ee195cf13419 at kinali.ch>, Attila Kinali writes:
>On Mon, 09 Mar 2020 13:44:59 +0000
>"Poul-Henning Kamp" <phk at phk.freebsd.dk> 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.


-- 
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