[SIUav8er]

GPS is RNAV, RNAV isnt necissarilly GPS. Basically RNAV is any form of navigation that is not ground based (even though it might USE ground based navaids to fix its position)

The original RNAV systems used VOR and DME to triangulate its position by determining the radial and DME from a certain station.

LORAN and OMEGA (thing of the past) are other forms of "RNAV" systems. I would also assume INS is RNAV as well although I could be wrong.

The whole LNAV, VNAV, LPV thing has to do with GPS WAAS(wide area augmentation system). In a nutshell, heres what it means:
LNAV is your basic IFR certified GPS that provides "lateral guidance" only. No vertical nav (glide slope).
VNAV is when the GPS uses WAAS to calculate a glide slope to follow so you wont have to "dive and drive" to the MDA, basically it just calculates a descent path, then displays it as a glide slope on a non precision approach.
LPV is localizer with precision vertical guidance. Basically it uses the WAAS signal to create an approach that is just as accurate as an ILS. In fact, LPV uses DA instead of MDA, so it is considered a precision approach.


Im not sure why theyre renaming GPS approaches RNAV approaches. Most of them require GPS to fly. im sure someone will chime in with better information here. Im too lazy to look this stuff up right now.

Hope that helped