Fault tolerance of the Global Navigation Satellite System using system-level diagnosis

The Global Navigation Satellite System (GNSS) is a space-based positioning system that can track aircraft, to within a few feet, anywhere in the United States of America. With augmentations based in other countries, the GNSS becomes a truly global positioning system, able to track aircraft anywhere on the globe with accuracies on the order of a few feet. We investigate the application of system-level diagnosis (SLD) to the GNSS to assess the diagnosability and fault tolerance of the system. We show, in a deterministic manner the number of faulty elements that can exist in the system and still allow for the accurate diagnosis of the system. Our deterministic approach is in contrast to other known probabilistic approach.