[Xastir] GNGGA vs GPGGA support

[Curt Mills]

To answer Jason's question about checksum, no I don't think we check it. We
probably should.

Also: APRS _can_ have increased resolution: Use APRS compressed mode. I
used to do that a lot, and it gives you precision of about a 2' by 3'
rectangle.

On Thu, Apr 11, 2019 at 1:02 PM Tom Russo <russo at bogodyn.org> wrote:

> I should point out that these updates only refer to handling of attached
> location receivers, and do not add support for raw NMEA posits as Jason
> had suggested.  It should not be super difficult to add that support, but
> it isn't done yet.
>
> On Thu, Apr 11, 2019 at 01:58:30PM -0600, we recorded a bogon-computron
> collision of the <russo at bogodyn.org> flavor, containing:
> > GNSS, GLONASS, Beidou, and Gallileo support is no on the main branch of
> > the Xastir repo, no fork needed.  Update your clone, and you should be
> able
> > to use Xastir with multi-constellation receivers now.  So far it has
> only been
> > tested with GPS and GNSS receivers, but it should work with all the
> others.
> >
> > If you try it and it doesn't work, please open a bug report on GitHub,
> and
> > we'll run it to ground.
> >
> > On Wed, Apr 10, 2019 at 10:56:38PM -0600, we recorded a bogon-computron
> collision of the <russo at bogodyn.org> flavor, containing:
> > > Turns out that the GNGGA/GNRMC vs. GPGGA/GNGGA issue is the reason for
> > > the newly opened issue #53 on github (
> https://github.com/Xastir/Xastir/issues/53),
> > > and I believe I have it fixed with pull request #58 (
> https://github.com/Xastir/Xastir/pull/58)
> > >
> > > If any users with GLONASS receivers that emit GNGGA/GNRMC sentences
> (such
> > > as the DRAWS hat for Raspberry Pi) would like to test it out,
> > > you can get it via:
> > >
> > >    cd <your clone>
> > >    git checkout master
> > >    git checkout -b tvrusso-feature-supportglonass master
> > >    git pull https://github.com/tvrusso/Xastir.git
> feature-supportglonass
> > >
> > > Then rebuild Xastir and try it out.
> > >
> > > The more folks I can get testing this the better.  I won't merge to
> master
> > > until I at least confirm that it helps the GN vs. GP thing.  As far as
> I can
> > > tell so far, I haven't borken it for GP.
> > >
> > > On Sun, Dec 02, 2018 at 02:52:06PM -0600, we recorded a
> bogon-computron collision of the <kg4wsv at gmail.com> flavor, containing:
> > > > I just started playing with a u-blox 8 family GPS.  It's capable of
> > > > receiving multiple GNSS simultaneously. At first glance this unit
> doubles
> > > > the number of available satellites just because it's listening to
> GLONASS
> > > > and GPS at the same time.
> > > >
> > > > Of course there's a downside. In APRS-land we're used to dealing
> with a
> > > > single "talker ID" that indicates we're dealing with GPS (the name
> of the
> > > > US system) - that's the "GP" in GPGGA and GPRMC. This system uses GN
> as the
> > > > talker ID when it's listening to multiple systems.  I can configure
> it to
> > > > use GPS only and get my familiar GPGGA, but I stop listening to a
> bunch of
> > > > available satellites when I do that.
> > > >
> > > > Since APRS has limited resolution we (APRS users) wouldn't benefit
> much
> > > > from increased accuracy, but we would get something from having a
> much
> > > > larger constellation available.
> > > >
> > > > Has anyone messed with these multi-GNSS receivers? Are the benefits
> that
> > > > seem obvious at first glance real?
> > > >
> > > > Would it be appropriate to think about code changes to Xastir (or
> other
> > > > clients but i don't use those) to use G[PLABN]GGA or G[PLABN]RMC
> instead of
> > > > restricting ourselves to GP only? There would be 2 cases here, once
> for the
> > > > attached GPS interface to determine our position, and the GPGGA APRS
> packet
> > > > type.  I'm actually considering using GGA and RMC packets to get
> increased
> > > > resolution on a non-144.39 tracking application.
> > > >
> > > > Does xastir verify the NMEA checksum from an attached GPS?
> > > >
> > > > -Jason
> > > > kg4wsv
> > > > _______________________________________________
> > > > Xastir mailing list
> > > > Xastir at lists.xastir.org
> > > > http://xastir.org/mailman/listinfo/xastir
> > >
> > > --
> > > Tom Russo    KM5VY
> > > Tijeras, NM
> > >
> > >  echo "prpv_a'rfg_cnf_har_cvcr" | sed -e 's/_/ /g' | tr [a-m][n-z]
> [n-z][a-m]
> >
> > --
> > Tom Russo    KM5VY
> > Tijeras, NM
> >
> >  echo "prpv_a'rfg_cnf_har_cvcr" | sed -e 's/_/ /g' | tr [a-m][n-z]
> [n-z][a-m]
>
> --
> Tom Russo    KM5VY
> Tijeras, NM
>
>  echo "prpv_a'rfg_cnf_har_cvcr" | sed -e 's/_/ /g' | tr [a-m][n-z]
> [n-z][a-m]
>
> _______________________________________________
> Xastir mailing list
> Xastir at lists.xastir.org
> http://xastir.org/mailman/listinfo/xastir
>


-- 
Curt, WE7U        http://we7u.wetnet.net        http://www.sarguydigital.com