How is GPS integrity maintained in an aircraft navigation system, and what happens if integrity is compromised?

How is GPS integrity maintained in an aircraft navigation system, and what happens if integrity is compromised?

• A. GPS integrity is maintained via receivers with RAIM/WAAS and fault detection; if compromised, the system reverts to inertial or other non-GPS navigation.
• B. GPS integrity is guaranteed by engine performance.
• C. GPS integrity is determined by barometric pressure.
• D. GPS integrity has no effect on navigation.

Answer: (A)

GPS integrity is maintained by the receiver using integrity monitoring and augmentation. The receiver continuously checks the consistency of the satellite signals with techniques such as Receiver Autonomous Integrity Monitoring (RAIM), which detects when one or more satellites are contributing faulty data, and by using satellite-based augmentation systems like WAAS (or equivalent) that provide integrity checks and corrections. This combination helps ensure that the position, velocity, and time solutions are trustworthy. If integrity is compromised or cannot be guaranteed, the navigation system has a safe fallback. It can drop unreliable satellite information and rely on other trusted sensors, most commonly the inertial navigation system, to continue providing navigation data. This switch maintains situational awareness and routing decisions while GPS data is treated as degraded or unavailable. The key point is that integrity monitoring helps catch faults, and when faults are detected, the system transitions away from GPS to preserve safe navigation. Engine performance or barometric pressure do not determine GPS integrity, and saying integrity has no effect on navigation isn’t accurate because compromised integrity directly affects the reliability of GPS-based navigation.

GPS integrity is maintained by the receiver using integrity monitoring and augmentation. The receiver continuously checks the consistency of the satellite signals with techniques such as Receiver Autonomous Integrity Monitoring (RAIM), which detects when one or more satellites are contributing faulty data, and by using satellite-based augmentation systems like WAAS (or equivalent) that provide integrity checks and corrections. This combination helps ensure that the position, velocity, and time solutions are trustworthy.

If integrity is compromised or cannot be guaranteed, the navigation system has a safe fallback. It can drop unreliable satellite information and rely on other trusted sensors, most commonly the inertial navigation system, to continue providing navigation data. This switch maintains situational awareness and routing decisions while GPS data is treated as degraded or unavailable. The key point is that integrity monitoring helps catch faults, and when faults are detected, the system transitions away from GPS to preserve safe navigation.

Engine performance or barometric pressure do not determine GPS integrity, and saying integrity has no effect on navigation isn’t accurate because compromised integrity directly affects the reliability of GPS-based navigation.