Performance-based navigation

In aviation, performance-based navigation (PBN) is a specification issued by the International Civil Aviation Organization (ICAO). In PBN, aircraft required navigation performance (RNP) and area navigation (RNAV) systems performance requirements are to be defined in terms of accuracy, integrity, availability, continuity, and functionality required for the proposed operations in the context of a particular airspace, when supported by the appropriate navigation infrastructure.

Source: Wikipedia — Performance-based navigation (CC BY-SA 4.0)