Re: [gpsd-users] GPSD / NTPD working - sort of

[Gary E. Miller]

Yo Rob!

On Thu, 26 Jan 2017 15:16:24 +0800
Rob Gunther <address@hidden> wrote:

> I decided it would be fun to build a GPS/PPS NTP server, I got it
> working but only partly and am looking for some input.

Cool.  What version of NTP?  Try this:

        # ntpd --version

> I built the system using an ODROID-C1+

I had an ODROID, I found it too unsupported by FOSS to be usefull.  YMMV.

> I have been following various guides but in large part am using the
> GPSD Time Service HOWTO

Good.

> ppstest works:

Good.

> gpsmon works, 

Good.

> So that all looks promising to me...

You skipped a step, what does ntpshmmon show? I exepct it to be good
as well.

Try this:

        # ntpshmmon

> I modified my ntp.conf to include:

Good.  Maybe drop minpoll and maxpoll to 2, but that is just a tweak.

> So in theory the two should be linked now.

How long did you wait?  I can take a day or two to stabilize.

> ntp never indicates it is reading anything from PPS either.

That would be a big problem, thus the need to ntpshmmon as above.

> *SHM(0)          .GPS.            0 l    3   16  377    0.000   69.955
>  42.229

Not good that ntpd is selecting SHM(0), maybe try a 'noselect' on it.

>  SHM(1)          .PPS.            0 l    -   16    0    0.000    0.000
> 0.000

Not good, no PPS.  I assume this is after at least 30 minutes of running?

> I have tried adjusting the time1 offset value (and setting it to 0)
> but the offset can go from -50 to maybe +80 and jitter jumps from 2
> to maybe 80 as well.

time1 for which refclock?  But that is a side issue.  Get your PPS
working first.

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

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    "If you can’t measure it, you can’t improve it." - Lord Kelvin

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