Re: DGPS / SBAS

[Nick Taylor]

Hi again

Please find attached logs from our device.

gps1.log is from startup with SBAS available and obtaining DGPS fix
gps2.log is when I moved antenna so that it couldn't see the SBAS satellites
gps3.log is after restart
gps4.log probably the most interesting - this is after a few days of no 
SBAS but device still showing DGPS - cgps image attached

Seems the gps chip is likely to blame here but please let me know your 
thoughts

Thanks and regards

Nick


On 30/11/2023 21:42, Gary E. Miller wrote:
> Yo Greg!
>
> On Thu, 30 Nov 2023 16:27:49 -0500
> Greg Troxel <gdt@lexort.com> wrote:
>
> > > Sadly no two firmware use the same definition for when to turn the
> > > DGPS flag on.
> > Agreed it's a mess but "DGPS" is obviously short for "Differential
> > GPS" and a receiver should only say it has that fixtype if it is
> > applying pseudorange corrections from either SBAS or some direct
> > injection of RTCM2, such as would happen with the old USCG beacons.
> Or RTCM3, or any of a number of prprietary protocols.
>
> But nothing mentioned that the corrections are actually improving
> the fix quality.
>
> > It seems pretty clear that either  this particular receiver is buggy
> > or that we're getting incorrect data about its behavior.
> Yeah, some raw NMEA may be interestsing.
>
> RGDS
> GARY
> ---------------------------------------------------------------------------
> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
>         gem@rellim.com  Tel:+1 541 382 8588
>
>             Veritas liberabit vos. -- Quid est veritas?
>      "If you can't measure it, you can't improve it." - Lord Kelvin

gps-logs.txz
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2023-12-04_10-39.png
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