Title: Satellite navigation - Wikipedia
Headings: Satellite navigation
Satellite navigation
Contents
Classification
History and theory
Applications
Global navigation satellite systems
GPS
GLONASS
BeiDou
Galileo
Regional navigation satellite systems
NavIC
QZSS
Comparison of systems
Augmentation
Related techniques
DORIS
LEO satellites
See also
Notes
References
Further reading
External links
Information on specific GNSS systems
Organizations related to GNSS
Supportive or illustrative sites

Content: As of September 2020
[update]
, the United States ' Global Positioning System (GPS), Russia 's Global Navigation Satellite System ( GLONASS ), China 's BeiDou Navigation Satellite System (BDS) and the European Union 's Galileo are fully operational GNSSs. Japan's Quasi-Zenith Satellite System (QZSS) is a (US) GPS satellite-based augmentation system to enhance the accuracy of GPS, with satellite navigation independent of GPS scheduled for 2023. The Indian Regional Navigation Satellite System (IRNSS) plans to expand to a global version in the long term. Global coverage for each system is generally achieved by a satellite constellation of 18–30 medium Earth orbit (MEO) satellites spread between several orbital planes. The actual systems vary, but use orbital inclinations of >50° and orbital periods of roughly twelve hours (at an altitude of about 20,000 kilometres or 12,000 miles). Contents
1 Classification
2 History and theory
3 Applications
4 Global navigation satellite systems
4.1 GPS
4.2 GLONASS
4.3 BeiDou
4.4 Galileo
5 Regional navigation satellite systems
5.1 NavIC
5.2 QZSS
6 Comparison of systems
7 Augmentation
8 Related techniques
8.1 DORIS
8.2 LEO satellites
9 See also
10 Notes
11 References
12 Further reading
13 External links
13.1 Information on specific GNSS systems
13.2 Organizations related to GNSS
13.3 Supportive or illustrative sites
Classification
GNSS systems that provide enhanced accuracy and integrity monitoring usable for civil navigation are classified as follows: GNSS-1 is the first generation system and is the combination of existing satellite navigation systems (GPS and GLONASS), with Satellite Based Augmentation Systems (SBAS) or Ground Based Augmentation Systems (GBAS). In the United States, the satellite based component is the Wide Area Augmentation System (WAAS), in Europe it is the European Geostationary Navigation Overlay Service (EGNOS), and in Japan it is the Multi-Functional Satellite Augmentation System (MSAS). Ground based augmentation is provided by systems like the Local Area Augmentation System (LAAS). GNSS-2 is the second generation of systems that independently provides a full civilian satellite navigation system, exemplified by the European Galileo positioning system.