What onboard system monitors GNSS integrity?

What onboard system monitors GNSS integrity?

• A. RAIM
• B. SBAS
• C. DME
• D. VOR

Answer: (A)

Onboard integrity monitoring for GNSS is provided by Receiver Autonomous Integrity Monitoring (RAIM). It checks the consistency of the GNSS measurements using the redundancy of available satellites. If a satellite’s measurement is unlikely or faulty, RAIM can detect the discrepancy and exclude that satellite, recomputing the position to keep the solution within integrity limits. The effectiveness of RAIM depends on having enough satellites in view; with a sufficient number, single-satellite faults can be detected and isolated. Ground-based or satellite-based augmentation systems like SBAS deliver additional integrity information to the receiver, which can aid decision-making, but the core onboard mechanism that actively monitors and verifies the GNSS signal integrity is RAIM. DME and VOR are separate navigation aids and do not perform GNSS integrity monitoring.

Onboard integrity monitoring for GNSS is provided by Receiver Autonomous Integrity Monitoring (RAIM). It checks the consistency of the GNSS measurements using the redundancy of available satellites. If a satellite’s measurement is unlikely or faulty, RAIM can detect the discrepancy and exclude that satellite, recomputing the position to keep the solution within integrity limits. The effectiveness of RAIM depends on having enough satellites in view; with a sufficient number, single-satellite faults can be detected and isolated.

Ground-based or satellite-based augmentation systems like SBAS deliver additional integrity information to the receiver, which can aid decision-making, but the core onboard mechanism that actively monitors and verifies the GNSS signal integrity is RAIM. DME and VOR are separate navigation aids and do not perform GNSS integrity monitoring.