Bob Noel wrote:

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


I confess I couldn't have guessed that )


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

No.

ADS-B does, but not TCAS.


Thanks, but how exactly does the TCAS get the coordinates of the
transponder it talks to, in determining whether or not an evasive
mechanism needs setting in? Anything like a +/- 50 meter accuracy there
would be disastrous.

Ramapriya