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Re: [gpsd-users] Garmin 18X-5Hz
From: |
Gary E. Miller |
Subject: |
Re: [gpsd-users] Garmin 18X-5Hz |
Date: |
Sat, 13 Aug 2016 12:50:50 -0700 |
Yo Robin!
On Sat, 13 Aug 2016 21:05:47 +0200
Robin Schwab <address@hidden> wrote:
> You convinced me that the uputronics is the better choice over the
> adafruit. I read the specs. The Adafruit is limited to 112 kbaud. The
> uputronics is four times as fast.
I agree, but either are fine, the diffferences are small.
> To my experience once you have established decent satellite signal
> latency and jitter on the UART are the biggest driver of inaccuracy
> in a GPS/computer setting. Latency is related to baud rate and number
> of nema sentences transmitted. Jitter happens because some nema
> sentences have a different length.
I really don't care. The PPS is orders of magnitude more precise
than the NMEA stream. NMEA is mostly just for sanity checking the PPS.
> I tried to make a standalone time server with GPS, gpsd and NTPd.
Works for me. Look at: gpsd-time-service-howto.txt. And at the
new NTPsec RasPi/NTP howto:
> The
> approach of David Taylor (who uses a network connected system) of
> giving the gpsd coarse clock a high stratum and the pps stratum 0 did
> not work because you cannot get a lock this way.
ntpd by design needs at least 3 good clocks. So you need PPS and
at least two other network chimers.
Set the PPS to 'prefer' and the NMEA to 'noselect'.
> So I hope very much that I can improve my results with the already
> ordered uputronics GPS.
How about these results:
Adafruit:
https://pi2.rellim.com/day/
Uputronics:
https://pi3.rellim.com/day/
I keep working to make them better.
> The Garmin GPS we are talking about in this thread will probably not
> even reach the results of the adafruit. It's only advantage is the
> ready-made housing.
Actaully, no so bad. Its main drawback is that it needs a very strong
GPS signal and a good skyview. Plus fiddling with the LVC is a PITA.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
address@hidden Tel:+1 541 382 8588
pgpz698t0YEaG.pgp
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- Re: [gpsd-users] Garmin 18X-5Hz, (continued)
- Re: [gpsd-users] Garmin 18X-5Hz, Roger Oberholtzer, 2016/08/18
- Re: [gpsd-users] Garmin 18X-5Hz, Gary E. Miller, 2016/08/12
- Re: [gpsd-users] Garmin 18X-5Hz, Robin Schwab, 2016/08/12
- Re: [gpsd-users] Garmin 18X-5Hz, Gary E. Miller, 2016/08/12
- Re: [gpsd-users] Garmin 18X-5Hz, Frank Nicholas, 2016/08/12
- Re: [gpsd-users] Garmin 18X-5Hz, Gary E. Miller, 2016/08/12
- Re: [gpsd-users] Garmin 18X-5Hz, Robin Schwab, 2016/08/13
- Re: [gpsd-users] Garmin 18X-5Hz,
Gary E. Miller <=
- Re: [gpsd-users] Garmin 18X-5Hz, David J Taylor, 2016/08/14
- Re: [gpsd-users] Garmin 18X-5Hz, Gary E. Miller, 2016/08/14
- Re: [gpsd-users] Garmin 18X-5Hz, Robin Schwab, 2016/08/14
- Re: [gpsd-users] Garmin 18X-5Hz, Gary E. Miller, 2016/08/14
- Re: [gpsd-users] Garmin 18X-5Hz, Robin Schwab, 2016/08/15
- Re: [gpsd-users] Garmin 18X-5Hz, Gary E. Miller, 2016/08/15
- Re: [gpsd-users] Garmin 18X-5Hz, Robin Schwab, 2016/08/15
- Re: [gpsd-users] Garmin 18X-5Hz, Gary E. Miller, 2016/08/15
- Re: [gpsd-users] Garmin 18X-5Hz, Alexander Carver, 2016/08/15
- Re: [gpsd-users] Garmin 18X-5Hz, Gary E. Miller, 2016/08/15