In article .com,
wrote:

Not really Bob. Most building, refinery and pipeline surveys accept a
+/- 0.8 centimeter variation, so it isn't pinpoint like in aircraft, I
think.

+/- 50+ meters is plenty accurate enough for aviation use in determining
lateral position. +/- 10 meters vertically would be wonderful but not always
obtained.


Btw, just out of interest - does TCAS use GPS data in some ways too?

No.

ADS-B does, but not TCAS.

--
Bob Noel
Looking for a sig the
lawyers will hate