Given this situation:

https://ozreport.com/22.141#8

and Andrej Kolar from Naviter's response:

Hi Davis,

Thanks for the link.

We see this as random GPS error. We've seen things like this happen before with
any combination of GPS / Flight recorder.

It was most obvious at one of the Cat-1 paragliding events where they tried to
score "finish cone" using GPS altitude. It was a mess. After landing pilots were
downloading all of their tracklogs, comparing GPS altitudes at finish to deliver
the best one. Differences were significant, up to 200 meters in altitude.

It's just how GPS works (or doesn't work if you like). In cases like this pilots
need to be scored by whichever tracklog is best for them.

Cheers,

Andrej Kolar

The Sporting Code states:

4.1

Flights will be verified using either GPS track log or live tracking data. When
live-tracking data is used as a primary source of scoring, pilots must be able
to produce GPS track logs as a back-up.

4. 2.1 Back-up Logger

A pilot may use multiple GPSs for verification and backup. Each pilot must
designate the primary logger that will be downloaded as the primary source of
scoring and the secondary one(s) to be used as backup, only in case of a
malfunction of the primary logger.

4. 2.2 Multiple Track Logs

In case of a malfunction of the primary logger, a pilot may submit evidence for
a flight using data from other GPS units, even if each only covers part of the
flight, providing that the Meet Director is satisfied the data was obtained by
the pilot during the task in question.

Here are the issues raised with this incident and these
regulations:

1) In an era where we use Flymaster trackers as the primary instrument for live
tracking and scoring, what does it mean that the "...pilot must designate the
primary logger that will be downloaded as the primary source of scoring..." What
exactly does the pilot have to do to designate a primary logger? Is that being
done? Can they designate their own flight instrument? How do they do that? How
can a logger than can not be referenced in flight by the pilot be used as the
primary logger?

2) Why must there be "... a malfunction of the primary logger,..." in order for
the "backup" logger to be used? Andrej argues that all the loggers need to be
looked at equally. But then do we just give the pilot their "best" track log? Do
we give the pilot the logger data that they have access to while flying? If the
loggers are approved for Category 1 competitions, does that mean we accept their
errors?

3) Is the new 0.05% error band realistic given these issues with approved
loggers? Why would a percentage value for the error band be used when we are
talking about absolute errors in GPS horizontal location determination?

4) I have been told that the Flymaster tracker has a 77 channel receiver and that
the Oudie 4 is rated "aviation quality" which means that it has at least 22
channels. How do we assess this difference?

5) Errors in GPS altitude are quite different (and supposedly of a much greater
magnitude) than errors in horizontal location. The GPS altitude errors show up a
number of times when comparing the two track logs.

6) The drift of the Oudie to the east displayed in the article linked to does
not appear to be random.

Personally I find this all interesting and will watch to see how things are
resolved.