✘TSIPv1 12 hour plot

[Gary E. Miller]

Yo All!

Seee attached 12 hour gpsprof plot from a new Trimble RES720 using the
new TSIPv1 protocol.  The RES720 routinely uses 40 or more "satellites"
from an indoor antenna, and start up alsmost instantly.  Sadly it has no
Battery Back Ram (BBR) so you setill need to wait for the UTC offset to
arrive in an Almanac subframe.

I say "satellites" because this is a multifrequency part, L1 and L5,
plus multi GNSS (GPS, GLONASS, Beidou, Galileo, etc.). gpsd counts 2
signals from one satellite as two "used satellites".

But for all this goodness, the acccuracy is only so-so.  Attached is a
12 hour plot from an antenna against a south facing window.  Note the
CEP(50) is on 2.36 m, CEP(95) is 4.64 m, and the CEP(99) 6.13 m!  As you
would expecct, the errors in AltHAE are worse.

The nice surprise is how good the skewness and hurtosis are.  That means
the remaining error are indeed getting close to Bayesian.  A rarity in
any GNSS receiver.

The big picture is that the new TSIPv1 driver is starting to look good,
but there are loose ends to tie up.  As you can see from the plot,
something wrong with the Statellites Used value.  Works in cgps, but not
in gpsprof.

So, time to think about the next release.  The reconnect thing has been
working well for a while, TSIPv1 is new, plus a lot of fixes here and
there.  Please start testing!

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

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