Yo Achim! On Tue, 30 Jan 2018 22:45:39 +0100 Achim Gratz via devel <devel@ntpsec.org> wrote:
> Gary E. Miller via devel writes:
> > I have some u-blox 6 that are USB mice. I get under 2 uS jitter on
> > a RasPi, but I have not compared them directly to a GPIO PPS. I
> > should add that to my long list. It takes a few days for the
> > clocks to settle in.
>
> Both my NaviSys stick (uBlox6) and puck (uBlox8) show ±1ms jitter over
> USB on the raspi.
> > I just powered up a SkyTrax NS-HP, Venus based. Took almost 48
> > hours before it reached best accuracy.
>
> Huh? the HP is an RTK receiver so you'd need a reference station to
> make use of that feature set.
Yes, I have two. But for this test I'm not using that feature set,
just basic PVT. BTW, that RTK is superb, I can resolve 1 cm changes
when I move the rover! But not how it is configured right now.
> The timing receiver is the NS-T and
> yes, if it cold starts and needs to pull the Almanach and do a
> auto-survey it'll be busy for a while.
Cold start was a few minutes, had been off for over 5 years, but
48 hours for things to really settle down. Maybe a factor of 3 better
after the 2 day wait.
I just added a u-blox 6 GPS mouse, and split the SkyTraq PPS to go into
GPIO 4 and GPIO 18. So three PPS on one RasPi. I'll post results later
today, first I finish to compiling the new kernel with the new multiple
PPS patch.
RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com Tel:+1 541 382 8588
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"If you can’t measure it, you can’t improve it." - Lord Kelvin
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