Dave Doe writes:

What is WAAS or RAIM etc etc - any aviation GPS technology - without GPS
itself?

WAAS is a navigation technology that relies on GPS. It is not _part_ of GPS.

These technologies are little more than GPS enhancements so that
aviators can use them to provided required and determined accuracy.

RAIM isn't even that much, but WAAS is an augmentation technology. The fact
remains that it isn't part of GPS itself.

GPS is otherwise useless for aviation - handy for a VFR pilot - but it
must not be relied on for either altitude or positional data - it's an
aid only.

It's very useful for lateral position in many circumstances, even for
aviation. The altitude data is too unreliable to be useful for aviation.