The document discusses the integration of Global Navigation Satellite Systems (GNSS), Geographic Information Systems (GIS), and wireless communications to enable location-based services. It outlines key events in satellite navigation systems, including the modernization of GPS in the US, development of the Galileo system in Europe, and reconstruction of the Russian Glonass system. The combination of GNSS, GIS, and wireless technologies has led to new applications involving vehicle and pedestrian navigation, transportation systems, and more accurate emergency location services.