What happens if one GPS fails?

What happens if one GPS fails?

• A. The system switches to inertial navigation
• B. The ADIRUs automatically get GPS data from the remaining GPS
• C. The GPS data is lost
• D. The remaining GPS stops updating

Answer: (B)

Redundancy in the navigation system is designed so a single failure doesn’t strip away position data. In this Airbus setup there are two GPS receivers and two ADIRUs (which integrate inertial data with air data). If one GPS fails, the system automatically routes the data from the remaining, working GPS to both ADIRUs. This keeps the navigation solution alive because the ADIRUs continue to compute position, velocity, and attitude using the still-available GPS updates plus the inertial reference. The system doesn’t switch to a purely inertial mode, and GPS data staying active prevents a loss of updates.

Redundancy in the navigation system is designed so a single failure doesn’t strip away position data. In this Airbus setup there are two GPS receivers and two ADIRUs (which integrate inertial data with air data). If one GPS fails, the system automatically routes the data from the remaining, working GPS to both ADIRUs. This keeps the navigation solution alive because the ADIRUs continue to compute position, velocity, and attitude using the still-available GPS updates plus the inertial reference. The system doesn’t switch to a purely inertial mode, and GPS data staying active prevents a loss of updates.