Although you may already be familiar with the term “GPS” (Global Positioning System), you may not have heard the term “GNSS” (Global Navigation Satellite System), which is used to describe the collection of satellite positioning systems, called "constellations," from various countries that are in operation or planned.
GPS (United States)
GPS was the first GNSS system and was launched in the late 1970s by the U.S. Department of Defense. The GPS constellation provides global coverage.
GLONASS is operated by the Russian government. The GLONASS constellation provides global coverage.
Galileo (European Union)
Galileo is a civil GNSS system operated by the European Global Navigation Satellite Systems Agency (GSA). Galileo provides global coverage.
BeiDou is the Chinese navigation satellite system. The BeiDou system provides global coverage with enhanced service for the China region.
The Navigation with Indian Constellation (NavIC) system provides service to India and the surrounding area.
The Quasi-Zenith Satellite System (QZSS) is a regional navigation satellite system that provides service to Japan and the Asia- Oceania region.
In Chapter 3, we will provide additional information about these systems.