Ionospheric Considerations for Wide Area GPS Augmentation Systems

ARAIM Challenges (LPV versus LNAV)• Vertical guidance versus lateral only– LPV versus LNAV– 556 m HAL to 35 m VAL– Major to hazardous criticality• Consequently– Redefinition of major fault– URA scrutiny– Prior probability based on URA failure– Correlated errors (within & between constellations)– Transparent discussion of constellation failures• Data link17