Peter Duniho wrote:

That is correct. The presumed 50 meter accuracy is constant throughout the
flight. It's not as though it's additive for each waypoint (or worse, as a
continuous function along the flight). Though frankly, even if it were,
you'd only be off by 500 meters after 10 waypoints which is still "no big deal".

Now I know why planes occasionally land on the wrong runway in IFR
conditions )

As for equipment skids and such, since I don't know the details of your
industry I can't really comment on that. But it seems to me that if you
require that level of detail and are using GPS to accomplish it, you must be
dealing with positioning these skids at a significant distance from wherever
they are referenced to. Otherwise, I'd think one would use more
"conventional" surveying techniques to determine position, orientation, etc.

When I began my career, there were only conventional surveying
equipment. These days, however, rarely do you get a client in the oil
and gas industry who'll accept anything but a GPS survey. Btw, we
engineers are barred too from all surveying, although we're responsible
for supervision and copping attendant liabilities. The actual task
itself is carried out by qualified surveyors who do nothing else

Ramapriya