GNSS signals — An overview

This paper provides an overview of Global Navigation Satellite System (GNSS) signals. Today, GNSS comprises two major constellations: (1) the United States' Global Positioning System (GPS), and (2) the Russian Federation's Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS). Two other major constellations are being deployed. Additionally, regional systems have been deployed or are planned. Whereas most GNSS timing receivers today rely only upon the legacy GPS signals, it is anticipated in the near future that multi-system receivers will become the norm. This paper describes the characteristics of each of the GNSS signals, and highlights the performance benefits that will be provided to the precise time and frequency community as the GNSS evolves.