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Re: [gpsd-dev] [Thumbgps-devel] Progress on Plain Jane
From: |
Eric S. Raymond |
Subject: |
Re: [gpsd-dev] [Thumbgps-devel] Progress on Plain Jane |
Date: |
Tue, 1 May 2012 19:09:17 -0400 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
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>
- Re: [gpsd-dev] [Thumbgps-devel] Progress on Plain Jane,
Eric S. Raymond <=