Re: [gpsd-users] gpsd time data not present on ntpd

[Gary E. Miller]

Yo Massimiliano!

On Sat, 29 Dec 2018 11:23:54 +0100
Massimiliano Fago <address@hidden> wrote:

> I start a gpsd with this command:
> 
> sudo gpsd -D 5 -N -n /dev/ttyAMA0 /dev/pps0

No need for the "-D 5 -N" anymore.  You confirmed that gpsd is working.


> sample NTP0 1546078291.330532005 1546078291.154584005 1546078291.000000000 0 
> -20
> sample NTP1 1546078291.331388005 1546078291.019129005 1546078291.000000000 0 
> -30
> sample NTP2 1546078291.332204005 1546078291.019129005 1546078291.000000000 0 
> -30

I'm not sure how you ended up with SHM(0), SHM(1) and SHM(2).  SHM(1) is
odd.

> After that I start ntpd with command:

How did you build ntpd?  Did you build it with all the refclock
drivers?

It would be helpful to see a log of how you built gpsd and ntpd.

> address@hidden:/home/pi# ntpd

You probably also want '-g' on the command line.

> # Prefer the precise clock at unit 1 over the imprecise one at unit 0.
> 
> refclock shm unit 1 prefer refid PPS

This is using the mysterious SHM(1).  You want unit 2 for the /dev/pps0

> refclock shm unit 0 refid GPS

Best to put this last so that ntpd will not use it.

> # GPS PPS reference
> server 127.127.28.2 prefer
> fudge  127.127.28.2 refid PPS

Now here is the SHM2(20
 
> # get time from SHM from gpsd; this seems working
> server 127.127.28.0
> fudge  127.127.28.0 refid GPS

But a duplicate of SHM(0).

> and with ntpmon I see:

Which looks like you forgot to build ntpd with refclock support.  The
build log will explain it.

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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