Re: [gpsd-users] Gpsd, ntpsec and system time offset

[Gary E. Miller]

Yo Massimiliano!

On Sat, 20 Jul 2019 13:12:48 +0200
Massimiliano Fago <address@hidden> wrote:

> have correctly (I think) configurated my system for take a GPS time.
> Gpsd wirking fine with PPS signal and ntpsec also working fine.
> My problem is that ntpsec not set the system time.
> In my ntp.conf (I have check more configuration) I have:

EWhat is your entire ntpd.con?

> # GPS Serial data reference (NTP0)
> server 127.127.28.0 minpoll 4 maxpoll 4
> fudge 127.127.28.0 time1 0.9999 refid GPS

You should never put SHM0 at the top of ntp.conf.  Put it
at the bottom.  Otherwise ntpd first tries you least accurate
time source.

Maybe even add noselect.

> # GPS PPS reference (NTP1)
> server 127.127.28.1 minpoll 4 maxpoll 4 prefer true
> fudge 127.127.28.1 refid PPS
> fudge 127.127.28.1 flag1 1

Put SHM1 first in the file, so ntpd tries to use you most accurate
source first.

> And with ntpmon I see in SHM(1) row:

After how long?  I presume it selected other chimers to use
before selectin SHM1.

> a large offset: -1000.0159.

Normal at startup.  ntpd tries to not jump the time unless you use the
-g option.  It slowly converges to the right time.  So that programs
that need accurate time do not get messed up by large time jumps.

> how I can tell to ntpsec to ignore the time difference and set the
> new time with a PPS o GPS reference?

It will eventually.  Or use -g to do a one time jump at startup.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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