GPS integrity monitoring and system improvement with ground station and multistationary satellite support

The authors propose a monitoring and warning system based on ground stations capable of supporting reliable operations. The same stations can also be used for the implementation of a differential mode of operation, through the transmission of measurement corrections relevant to the tracked GPS (Global Positioning System) satellites. A combined operation of the stations is implemented in this manner. For civil aviation applications, the system operation can be enhanced with the integration of four multistationary satellites within the GPS space segment. The addition of four multistationary satellites will extend the integrity monitoring and system availability worldwide up to very high latitudes. The adoption of multistationary satellites presents valuable advantages over geostationary satellites. The results of some preliminary simulations are presented for the integrity monitoring and the system availability improvement