Oh dear here we go again. Reference please
I don't know what you mean by this. Basic fact - the GPS ground segment has its own integrity monitoring system, but due to the physical location of the stations around the world alerts can take some hours - no good for aviation, hence the development of RAIM and its equivalents, plus SBAS and GBAS. These developments were mainly to resolve the integrity issue, along with an improvement in accuracy.
Hey, it works..... and I think if you read my post again you will find we are on the same side.....
