Satellite navigation: Present and future

The Global Positioning System serves one billion civil users, with applications including navigation for cars, aircraft, ships, spacecraft, pedestrians, and emergency services; time transfer for telecommunications, finance, and power delivery; and a breadth of scientific uses. Cognizant of this utility, the Russians are rejuvenating their satellite navigation system, and new systems are being fielded by China, Japan, India, and Europe. Taken together, this Global Navigation Satellite System will provide geometric diversity, with over one hundred navigation satellites, all with triple frequency diversity for civil use. This paper will briefly describe the technology, with a focus on aviation applications.