Bloggs:
Forget the concepts of "Non-Precision" and "Precision". Because there are now approaches that are flown "similar" to an ILS eg LPV, GLS, Baro VNAV, RNP-AR ie they give proper, legalised vertical commands which you must follow (like you follow a GS), the old "precision" concept ie provision of a GlideSlope, has become muddied. That's why the system introduced 2D (2 dimensional, the old MDA-type approaches) and 3D (approaches flown with vertical guidance/commands ie 3 dimensional that include ILS and RNP-AR and indeed BaroVNAV. All 3D approaches are the same: follow the pitch commands down to the DA and then go around if not Visual.
FD, an "APV" is an APproach with Vertical Guidance", a 3D approach. Flown exactly like an ILS, but obviously not one, in the historical sense of the "precision" concept. The "BARO" part signifies the altimeter/QNH is being used to provide vertical commands, as opposed to a GLS, where I assume the GPS gear is used to provide the "glidepath" to follow. An RNP-AR would therefore be a type of Baro-VNAV, I suppose, which is of course an APV!
Good summary!
Having said that I think ICAO is full of it on LPV. It walks and quacks just like a CAT I ILS except LPV is always rock solid unlike some ILS facilities.
Further, the fact that the U.S. (perhaps other countries with SBAS as well) use the exact same obstacle clearance surfaces and lateral dimensions as used for CAT I ILS says legions.