RAIM is best described as which of the following?

• A. Ground-based augmentation system
• B. GNSS receiver function that monitors satellite signals to detect errors within itself and confirm the integrity of the GPS position solution
• C. Radar system for terrain avoidance
• D. Wind shear detection system

Answer: (B)

RAIM is about the receiver’s own ability to verify that the GPS position it computes is trustworthy. It works by the GNSS receiver inspecting the signals from multiple satellites and checking the consistency of the measurements to detect any errors that could affect the position result. In essence, it provides an internal check on integrity, using redundancy among the satellite signals to confirm whether the solution can be trusted.

That’s why the best description is a GNSS receiver function that monitors satellite signals to detect errors within itself and confirm the integrity of the GPS position solution. It doesn’t rely on external augmentation, and it’s not a radar terrain-avoidance system or wind-shear detector.