RAIM accuracy limit for the En-Route phase is closest to what value?

RAIM accuracy limit for the En-Route phase is closest to what value?

• A. 5.0 NM
• B. 2.0 NM
• C. 0.3 NM
• D. 1.0 NM

Answer: (B)

RAIM (Receiver Autonomous Integrity Monitoring) checks GPS signals to ensure the position solution is trustworthy, and the RAIM accuracy limit is the maximum position error that the system is designed to detect and alert you about if a fault occurs. For the en-route phase, you’re navigating over long distances on airways, so a moderate integrity margin is appropriate—fast fault detection with a practical accuracy level. That balance is commonly cited as about 2 nautical miles. The other values relate to different flight phases: 0.3 NM is a tighter limit typical of terminal or approach/precision requirements, 1.0 NM is not the standard en-route figure, and 5.0 NM would be looser than what en-route RAIM aims to guarantee. So, the en-route RAIM accuracy limit being around 2.0 NM makes it the best match.

RAIM (Receiver Autonomous Integrity Monitoring) checks GPS signals to ensure the position solution is trustworthy, and the RAIM accuracy limit is the maximum position error that the system is designed to detect and alert you about if a fault occurs. For the en-route phase, you’re navigating over long distances on airways, so a moderate integrity margin is appropriate—fast fault detection with a practical accuracy level. That balance is commonly cited as about 2 nautical miles. The other values relate to different flight phases: 0.3 NM is a tighter limit typical of terminal or approach/precision requirements, 1.0 NM is not the standard en-route figure, and 5.0 NM would be looser than what en-route RAIM aims to guarantee. So, the en-route RAIM accuracy limit being around 2.0 NM makes it the best match.