What type of approaches utilize WAAS and/or GBAS for course guidance?

The correct choice is RNAV because it stands for Area Navigation, which allows aircraft to fly on any desired flight path within the coverage of GPS or other navigation aids. RNAV approaches utilize WAAS (Wide Area Augmentation System) and GBAS (Ground-Based Augmentation System) technologies to provide improved accuracy, integrity, and availability of navigational signals.

WAAS enhances the GPS signal by correcting errors caused by the ionosphere and other factors, making RNAV approaches more reliable and precise for approaches to airports. Similarly, GBAS provides differential corrections to GPS signals, offering a robust alternative for precision approach operations.

In contrast, while ILS (Instrument Landing System) is primarily a ground-based system that uses localizer and glideslope signals for guidance, VOR (Very High Frequency Omni Directional Range) relies on directional radio signals transmitted from ground stations. GPS, while critical for navigation and approaches, represents a form of positioning rather than the approach method itself. Therefore, RNAV is uniquely suited to utilize technology like WAAS and GBAS for course guidance.