Plazbot, careful, your comment on RNAV is incomplete -
ICAO PBN Manual (Doc. 9163)…
RNAV System - A navigation system which permits aircraft operation on any desired flight path within the coverage of station-referenced navigation aids or within the limits of the capability of self-contained aids, or a combination of these. An RNAV system may be included as part of a Flight Management System (FMS).
RNAV Operations - Aircraft operations using an area navigation system for RNAV applications. RNAV operations include the use of area navigation for operations which are not developed in accordance with the PBN Manual.
RNP Systems and Operations … as you suggested, (enhanced) area navigation systems and procedures compliant with ICAO (or EASA) requirements for RNP implementations. At present en-route (BRNAV & RNAV5) and terminal (PRNAV) navigation in ECAC area is possible without RNP equipment.