Re: [gpsd-dev] [Thumbgps-devel] Progress on Plain Jane

[Eric S. Raymond]

Gary E. Miller <address@hidden>:
> As you can see the NMEA/USB short term jitter is about 2 milliSec and
> the PPS/USB time is about 0.5 milliSec jitter.  Long term NMEA/USB drift
> is quite a bit larger, maybe 100 milliSec or more.
> 
> So the jitter of PPS over USB is about 50x worse than PPS over GigE, but
> I think for the purposes at hand pretty good.  Of course I expect the
> results to be worse when run on a single core router.

That's excellent news.  0.5msec jitter is as good as we could have
expected and exactly what one would predict from a max error of 1msec
due to polling interval. The long-term NMEA/USB drift is consistent
with previous observations by Hal Murray and myself.

Do you consider the GR-601 with this mod to be ready for production?
Should we give Navisys the green light on GPSD compatibility?  I see
no reason not to at this point, but you're doing the testing so you
make the call.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>