Originally Posted by
pilotnik86
that RAIM is not a type of augmentation.
I can see how the definition of ABAS in EU-OPS as led you astray, its suggestive last sentence is occluding the principles, although it does say what you quoted already.
RAIM definition is much clearer
‘Receiver autonomous integrity monitoring (RAIM)’ means a technique whereby a GNSS receiver/processor determines the integrity of the GNSS navigation signals using only GNSS signals or GNSS signals augmented with altitude. This determination is achieved by a consistency check among redundant pseudo-range measurements. At least one satellite in addition to those required for navigation has to be in view for the receiver to perform the RAIM function.
RAIM is not improving the GNSS signals, nor adding another source for position calculation, but merely a monitoring tool. Assuming otherwise will lead to doubtful findings that at some point, where I believe you may have already arrived, stop making any sense. The answer you need is not available until proper names and meanings are used, no matter whose fault they might be.
I.e. "GPS Required" do not specifically mean "INS (VOR/LOC) not permitted". The FMS/MMR internal logic will take care to use the most accurate and reliable coordinate source - and in such voting process RAIM is essential.