Influence of GNSS Integrity Monitoring on Undetected Fault Probabilities for Single and Multiple Fault Events

Abstract

Cases of multiple simultaneous faults are generally considered low probability in integrity analysis of GNSS augmentation systems. This assumption is not necessarily valid given the sensitivity limitations of practical integrity monitors. This paper introduces a method to account for monitor sensitivity in quantifying the probability that undetected faults occur. Analysis of the two-fault case suggests that the conventional method of designating a small integrity risk allocation to cover all multiple-fault events does not necessarily ensure integrity for difficult-to-detect, small, and moderate-sized faults.