Performance-based navigation is a generic term that encompasses the principles of both area navigation (RNAV) and required navigation performance. ICAO saw that area navigation and required navigation performance were being specified differently by national aviation authorities all over the world, which ultimately makes international aviation more complex and costly for operators. So ICAO decided to develop "a globally harmonised concept that meets current operational requirements while remaining flexible enough for future requirements".
It boiled the PBN concept down to two categories: the first for aircraft with no on-board performance monitoring and alerting systems, but which can comply with any of the four present RNAV accuracy levels between 10nm (18.5km) and 1nm and the second for aircraft with on-board monitoring and alerting systems, but that can operate to any of the RNP accuracy specifications from 4nm to 0.3nm plus future requirements like 4D navigation.
Apart from standardising global navigation performance categories, the advantage of PBN is that it does not specify navigation aids nor on-board equipment, only the navigation performance category an aircraft can meet in any given environment.
Source: Flight International
