SUPPLEMENTAL SYSTEM FOR A SATELLITE BASED APPROACH DURING LOW VISIBILITY CONDITIONS

A method of supplementing a satellite based augmentation system approach during low visibility conditions is provided. The method includes acquiring satellite range measurements and additional measurements from at least one additional onboard independent sensor. Core sigma values are assigned for satellite range measurements and for each additional measurement from the at least one additional onboard independent sensor. A weighted position solution is determined using the acquired satellite range measurements, the acquired additional measurements and the assigned core sigma values. A discriminator is applied that utilizes vehicle positions derived from the acquired satellite range measurements and from the additional measurements to determine if a fault is present in the weighted position solution. An alert is generated if an output of the discriminator is outside a set tolerance value needed for low visibility operation.