Instrument Rating Exam · Mock exam

Baro-aiding in a GNSS receiver allows RAIM with only 4 satellites instead of 5 because:

• A.Baro-aiding adds extra artificial satellite signals to the solution by triangulating the pressure data
• B.Barometric altitude provides a fifth constraint (vertical position), replacing the fifth satellite in the integrity calculation
• C.The barometric altimeter continuously corrects the GPS signal for ionospheric propagation delays en route
• D.Baro-aiding is used only for vertical guidance on LPV approaches, thereby freeing one satellite for RAIM