ABSTRACT
Availability is a core attribute of Global Navigation Satellite System (GNSS) and many topics are studied in this area. However most of them are about a part of GNSS, which is single satellite availability, navigation constellation availability or the availability of ground stations. Very few studies are concerned with the availability of the whole system. In view of this, the availability simulation modeling of the whole GNSS including space segment and ground segment were studied in this paper. The influence of satellite failure, interruption, coverage and ground station fault, repair etc. on system operation was considered to establish the model. Then the simulation logic was developed to simulate the operation of navigation system. Based on the STK/MATLAB hybrid simulation, the service availability of the GPS for Beijing was analyzed finally. The simulation results verify the applicability of the model and the simulation algorithm.
