NMEA but no PPS in ntp, Ubuntu 18.04.5

[Gary E. Miller]

Yo Steve!

On Thu, 3 Dec 2020 08:42:59 -0600
Steve Bourland <sbourland@swri.org> wrote:

> Yo Gary!
>    I've tried to attach the output of:
> 
> # gpsd -N -n -D 6 /dev/ttyS0 |& fgrep PPS
> 
> as a text file attachment, I hope it comes through in an easier to
> read format for you.  I had to add the -N to keep from daemonizing to
> get the output.  

Sorry, I forgot the -N.  That shold be an FAQ.

>    If I am reading it correctly, it looks like it is activating 
> ntpshm link #1 as we had hoped/expected (using SHM(2) did not solve
> the problem, which I think is now expected given the
> ntpshm_link_activate line).  

After looking at the code, I decided the log never tells you which SHM()
was used.  The ntpshm_link_activated just tells you 0 == Serial, 1 ==
PPS, not which SHM.  That logging is improved in git head.

> It look like the PPS thinks there is no
> fix, although cgps reports one:  

Yup, cgps thinks 3D, but PPS thinks otherwise.

gpsd:INFO: PPS:/dev/ttyS0 Assert hooks called clock:
1607005294.000156294 real:  1607005294.000000000: no fix

Very odd.  Hard to debug threading remotely.

Did you ever get aound to getting ntpd to listen to SHM(0) and SHM(2)?

> As to why I have the '-b' in the command line, that is a carryover
> from my "standard" gpsd configuration starting way back in Ubuntu
> 10.04's time frame I believe, I've just dragged it along...will ditch
> it moving forward now that I understand the broken binaries it is
> dealing with aren't mine :)  

Depending you your GNSS receiver that change may help, or not.  The
benefit, depending on model is that gpsd may optimize the sentences that
your receiver sends.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  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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