Re: [Thumbgps-devel] "Plain Jane" timing GPS is working!

["Eric S. Raymond" <esr@thyrsus.com>]

Dave Taht <dave.taht@gmail.com>:
> Expect light participation from me here through may 5. I would certainly be
> open here to a discussion of 'now that we have good time, and geolocation,
> what can we effectively measure with it, and with what tools'...

Good time isn't quite a done deal yet.  There are some relatively minor 
changes to gpsd and a bit more hardware testing between here and there.
I'd say two weeks, assuming we don't run into any boojums.  And I won't
sign off that the job is *really* finished until we can document hard bounds
on the jitter using something like the test rig Patrick Maupin is trying
to build.

By the way, I've had a third GPS vendor - a U.S. outfit called Parallax
Systems - get back to me with interest in the Plain Jane timing-GPS mod
(connect 1PPS to DCD in a stock design using SiRF+PL2303 or functional
equivalents). Had a long, friendly phone conversation with one of
their design guys.

For those of you not paying full attention recently, I have
engineering samples of Plain Jane from UniTraq - not yet verified that
these work because I have to mod gpsd so it won't time out the PPS
thread before it gets sat lock.

Meanwhile, Unitraq's test engineers in Shenzhen have shown me a gpsd log 
including PPS events seen over USB.  But we need to tell gpsd's noise
filter to be a bit less picky; for some reason it doesn't like the
pulse width and is rejecting those.

So we have two vendors actively cooperating on Plain Jane product
development and may have a third shortly.  This is all good; my
ideal outcome would be multiple sources, with other vendors starting 
to pick up that they need to supply 1PPS to stay competitive and it 
becoming a stock feature on all new low-end GPS mice within a year.

Actually, it still kind of blows my mind that I've been able to
social-engineer all this with a handful of emails.  Woulda been the
stuff of cyberpunk novels before the century turned...
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>