Re: [gpsd-users] Is GPSD receiving PPS?

[Gary E. Miller]

Yo Jon!

On Fri, 04 Mar 2016 02:57:22 -0600
"Jon Brase" <address@hidden> wrote:

> > Gpsd works fine if you just specify the both devices:
> >     gpsd /dev/tty[your-gps] /dev/pps[your-pps]
> 
> 
> OK. It's not made really clear in the documentation that specifying  
> anything but a serial device is even an option.

Well, the PPS device is a serial device.  So in the end serial
devices are still the only options.

I see you are right, it is not in the gpsd doc.  Improvements to the
documentation are always welcome.  Can you suggest improvements to the
RasPi part of the INSTALL doc?


> In any case, I'm now launching gpsd with the command line:
> 
> gpsd -n /dev/ttyAMA0 /dev/pps0 -F /var/run/gpsd.sock
> 
> to launch it as a daemon at boot, or:
> 
> gpsd -F /var/run/gpsd.sock -nND 5 /dev/ttyAMA0 /dev/pps0

Using -D slwos down the output, and will affect your time accuracy, so
only use that for debug.

A better way to narrow in on time:

gpsd -F /var/run/gpsd.sock -nND 5 /dev/ttyAMA0 /dev/pps0 |& egrep 'PPS|NTP'


> (The port change there is because Raspbian uses systemd, whose init
> seems to "helpfully" grab ports daemons started in boot scripts and
> pass traffic on those ports through to the process. If the process
> dies or the service is stopped, init doesn't let go of the port. So
> if I shutdown the boot-time daemon to run gpsd in a terminal for
> debugging, I have to start it on a different port).

Anothre reason to shoot systemd in the head.  I hope someone finds a
better workaraound.

> In any case, with that command line, I am now seeing different output
> with regards to PPS. GPSD still seems to be having trouble getting
> valid PPS data,

How do you know that?

> but ppstest still seems to have no trouble.

Except the preivously noted bug about the clear.

> I've attached the output I'm getting from GPSD.

The list server strips attachments.  So inline, or pastebin.

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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