GPS is one of two Global Navigation Satellite Systems (GNSS), with a third currently under development. The two active GNSS systems are Global Positioning System (GPS), which is operated by the United States military and the Global Navi-gation Satellite System (GLON-ASS), which is operated by the Russian Federation military.
There is also one Chinese Regional Satellite System called Beidou. A new GNSS is being developed by the European Union (EU), called Galileo, while Japan is planning a Quasi-Zenith Satellite System (QZSS) that will increase the integrity of the current systems and also increase the number of visible satellites in dense urban areas.
All of these changes to Global Navigation Satellite Systems will have a marked impact on surveyors and other users in the world. The attainable accuracy will increase; reliability and satellite availability will improve and the strength of the navigation signals will be increased.
