Editing Satellite navigation (section)

==Classification==
{{further|GNSS augmentation}}
GNSS systems that provide enhanced accuracy and integrity monitoring usable for civil navigation are classified as follows:<ref name=generations>{{cite web |url=http://www.ifatca.org/system/files/public_docs/gnss.pdf |publisher=IFATCA |title=A Beginner's Guide to GNSS in Europe |access-date=20 May 2015|archive-url=https://web.archive.org/web/20170627221451/http://www.ifatca.org/system/files/public_docs/gnss.pdf|archive-date=27 June 2017|url-status=dead }}</ref>

* '''{{visible anchor|GNSS-1}}''' is the first generation system and is the combination of existing satellite navigation systems (GPS and GLONASS), with [[Satellite Based Augmentation System]]s (SBAS) or [[Ground Based Augmentation System]]s (GBAS).<ref name=generations/> 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); in Japan, it is the [[Multi-Functional Transport Satellite|Multi-Functional Satellite Augmentation System]] (MSAS); and in India, it is the [[GPS-aided GEO augmented navigation]] (GAGAN). Ground-based augmentation is provided by systems like the [[Local Area Augmentation System]] (LAAS).<ref name=generations/>
* '''{{visible anchor|GNSS-2}}''' is the second generation of systems that independently provide a full civilian satellite navigation system, exemplified by the European Galileo positioning system.<ref name=generations/> These systems will provide the accuracy and integrity monitoring necessary for civil navigation; including aircraft. Initially, this system consisted of only Upper [[L Band]] frequency sets (L1 for GPS, E1 for Galileo, [[L Band|and]] G1 for GLONASS). In recent years, GNSS systems have begun activating Lower [[L Band]] frequency sets (L2 and L5 for GPS, E5a and E5b for Galileo, [[L Band|and]] G3 for GLONASS) for civilian use; they feature higher aggregate accuracy and fewer problems with signal reflection.<ref>{{cite web|url=https://gssc.esa.int/navipedia/index.php/Galileo_General_Introduction|title=Galileo General Introduction - Navipedia|website=gssc.esa.int|language=en|access-date=2018-11-17}}</ref><ref name="autogenerated3">{{cite web|url=https://gssc.esa.int/navipedia/index.php/GNSS_signal|title=GNSS signal - Navipedia|website=gssc.esa.int|language=en|access-date=2018-11-17}}</ref> As of late 2018, a few consumer-grade GNSS devices are being sold that leverage both. They are typically called "Dual band GNSS" or "Dual band GPS" devices.

By their roles in the navigation system, systems can be classified as:
* There are four global satellite navigation systems, currently [[Global Positioning System|GPS]] (United States), [[GLONASS]] (Russian Federation), [[Beidou]] (China) and [[Galileo (satellite navigation)|Galileo]] (European Union).
* Global Satellite-Based Augmentation Systems (SBAS) such as [[OmniSTAR]] and [[StarFire (navigation system)|StarFire]].
* Regional SBAS including WAAS (US), EGNOS (EU), MSAS (Japan), [[GPS-aided geo-augmented navigation|GAGAN]] (India) and SDCM (Russia).
* Regional Satellite Navigation Systems such as India's [[Indian Regional Navigation Satellite System|NAVIC]], and Japan's [[QZSS]].
* Continental scale Ground Based Augmentation Systems (GBAS) for example the Australian GRAS and the joint US Coast Guard, Canadian Coast Guard, US Army Corps of Engineers and US Department of Transportation National [[Differential GPS]] (DGPS) service.
* Regional scale GBAS such as CORS networks.
* Local GBAS typified by a single GPS reference station operating [[Real Time Kinematic]] (RTK) corrections.

As many of the global GNSS systems (and augmentation systems) use similar frequencies and signals around L1, many "Multi-GNSS" receivers capable of using multiple systems have been produced. While some systems strive to interoperate with GPS as well as possible by providing the same clock, others do not.<ref>{{cite journal |last1=Nicolini |first1=Luca |last2=Caporali |first2=Alessandro |title=Investigation on Reference Frames and Time Systems in Multi-GNSS |journal=Remote Sensing |date=9 January 2018 |volume=10 |issue=2 |pages=80 |doi=10.3390/rs10010080 |bibcode=2018RemS...10...80N |doi-access=free|hdl=11577/3269537 |hdl-access=free }}</ref>