When the operation faults of satellite navigation system occur, its navigation service performance will be affected. The regional satellite navigation constellation consists of GEO, IGSO and MEO. The space environments and orbit maneuvering situations of the satellites are different, because of their special orbit heights and types. Therefore, satellite fault situations need to be further refined and analyzed. The previous researches mostly discussed the two situations including orbit maneuvering and single event upset, but there is no considering about the randomness of orbit maneuvering or the fault situations of single event upset in different satellite work units. In this paper, the fault situations of single event upset are divided into four work units, including navigation task processing unit, spread spectrum receiver unit, satellite platform unit and satellite clock unit. Then, the specific fault simulation model is set up by the algorithm named Monte Carlo, and all the possible fault types of three kinds of satellites including GEO, IGSO and MEO are analyzed by simulation. Finally, the mathematical model of satellite availability is established, and then the satellite availabilities in different situations of fault types are analyzed comparatively.
