What does Receiver Autonomous Integrity Monitoring (RAIM) do?

Receiver Autonomous Integrity Monitoring (RAIM) is a critical functionality in GNSS (Global Navigation Satellite System) receivers, particularly in aviation. Its primary role is to ensure the integrity of satellite signals by continuously monitoring and analyzing the signals received from the satellites. This process involves checking for potential errors or anomalies in the satellite positioning data and quickly determining whether the information is accurate enough to be used for navigation.

The importance of RAIM lies in its ability to provide warnings to the user if any satellite is compromised or if the position accuracy has degraded to an unacceptable level. This enhances the safety and reliability of navigation systems without needing external references, which is crucial for many aviation applications, especially during approaches and landings.

The other options do not align with RAIM's specific function, as it does not directly enhance fuel efficiency, adjust flight paths automatically, or calculate weather changes. Each of these tasks falls under different technology domains or systems in aviation.