Instrument Rating Exam · Mock exam

GBAS (Ground Based Augmentation System) improves GPS accuracy by:

• A.Adding additional dedicated augmentation satellites to the GPS constellation over the service region
• B.Using the aerodrome's surface movement radar to independently measure and correct the GPS position
• C.Measuring GPS errors using reference receivers at known positions and broadcasting corrections to aircraft nearby (~23 km)
• D.Providing supplementary VHF ranging data from the ground station antenna to augment GPS positioning