Re: NTPsec reports excessive jitter from GPSD/KPPS SHM

[Gary E. Miller]

Yo Greg!

On Mon, 09 Mar 2020 12:43:07 -0400
Greg Troxel <address@hidden> wrote:

> "Nick Burkitt" <address@hidden> writes:
> 
> > # GPS Serial data reference (NTP0)
> > refclock shm unit 0 refid GPS noselect
> > # GPS PPS reference (NTP1)
> > refclock shm unit 2 minpoll 3 maxpoll 3 refid PPS prefer  
> 
> Perhaps this is documented in gpsd, but I wonder why there is unit 0
> and unit 2, vs 1.

gpsd assigns SHM()s in pairs.  The first pair is the first device
on the command line.  The second pair is the second device on
the command line, etc.

The pair allows gpsd to report serial (GPS) time and PPS time
separately.  If gpsd does not have two times for a device, then
only the first one is used.

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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