What is the difference between RNAV and RNP navigation?

RNAV (Area Navigation) enables aircraft to fly any desired path using navigation aids or autonomous systems, not limited to direct routes between ground stations. RNP (Required Navigation Performance) adds integrity and monitoring requirements to RNAV. Key differences: RNP requires onboard performance monitoring and alerting (RNP APCH, AR approaches), RNP specifies lateral accuracy requirement in nm (e.g., RNP 0.3 = 0.3 nm 95% of time), and RNP includes containment (2x accuracy defines containment). Approach types: LNAV (lateral guidance), LNAV/VNAV (adds vertical), LPV (GPS precision similar to ILS), and RNP AR (special approval required, curved paths possible). RNP enables approaches to runways without ground-based navaids.