[rgr331]

What is the point of a RAIM prediction on a flat earth?

Seems that if GPS is actually an eLORAN system, then any aircraft at any positive altitude could receive the eLORAN signal from many many many eLORAN stations. 

But, for some reason, befor I fly a GPS approach, I need to do a RAIM predict to make sure my aircraft will have line of sight view to at least 4 GPS satellites.  It seems like a procedure I could omit on a flat earth.

[Rounder]

For those of us who aren’t pilots, the Wikipedia article about RAIM (Receiver autonomous integrity monitoring) is very interesting.

It is posts like this one that keep me coming back to tfes.  This led me to learn something new, than you for that!