Agree with the previous posters re. practical application (e.g. Garmin 430/530 will show any RAIM warning where it's really hard to miss), but for instrument tests and renewals, there's a PASS/FAIL item on the form for the RNAV and GPS arrival approaches that reads:
- GPS integrity checked
I am being taught just to flick over to the satellite page and ensure there's at least reception from four satellites. Takes less than five seconds all in, but something that's easy to miss like the NDB IDENT ON, and it's an automatic FAIL if you miss it, just like going under the minima
