[LinuxPPS] [PATCH]

[Cirilo Bernardo]

>
> > Maybe first enable some NMEA stuff to see the amount of sats.
> > Next we'd like to set an absolute minimum for a dependable PPS..
> >
> > OK, we're getting offtopic w.r.t. LinuxPPS.
> >
> Don't think so.
> This discussion broaden our view and helps design the right interface.
> PPS is not alone in doing the time-job.
>
> Bernhard
>

I thought about this problem for a few days last year and since I'm
working with an embedded system which no one else should alter, my
solution was to write a GPS driver from scratch.  However, I cannot
recommend this approach for general use; although it works very well,
I'm sure no one wants a proliferation of not only GPS-specific but
board-specific drivers.  If someone wants to, they can post to the
NTPD list and see what the opinion is on using the NMEA driver to
determine if the PPS is good.  If I remember correctly, gpsd does this
by using the satellite tracking message; I think it was Eric S.
Raymond who commented that the satellite tracking message varies from
manufacturer to manufacturer so decoding that message is not trivial.
 Maybe this whole thing is not an issue if people can use gpsd and the
NTP patch for it?  In my case, unfortunately, gpsd was not suitable.