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Glossary of Terms
Cellular Positioning
Cellular positioning consists of recording the location of detected cellular towers into a database. When the database is later queried by a device in the vicinity of previously detected towers, the position of the device may then be estimated. Cellular positioning augments GNSS positioning in areas where a GNSS receiver may not hear sufficient numbers of satellites to establish a fix. It is a useful technology for certain Location-Based Services, including indoors, but not an absolute replacement of GNSS due to lower accuracy and inconsistent coverage. The accuracy of cellular positioning may range from 150-500m in urban areas and can be much larger in suburban and rural areas.
GLONASS - GLObal NAvigation Satellite System
GLONASS is the global navigation satellite system (GNSS) deployed and operated by the Russia Space Forces. It was launched in 1976 and was completed in 1995, but fell in disrepair due to the Russian economy. It has since been refurbished and provides full global coverage since 2010 with 22 of 24 satellites deployed. Several chipset vendors are now planning the incorporation of multi-GNSS support (e.g. GPS, GLONASS, Galileo) to take advantage of the increased number of available positioning satellites. [Read more].
GNSS - Global Navigation Satellite System
Global Navigation Satellite Systems is the generic term for any satellite navigation system, such as GPS, GLONASS, Galileo and several others, that enable receivers to globally and precisely determine both time and position based on signals broadcast from multiple orbiting satellites. [Read More]
GPS - Global Positioning System
GPS is the global navigation satellite system (GNSS) deployed and operated by the US Department of Defense. It was launched in 1973 and consists of 24 satellites orbiting the earth and providing global and free positioning to anyone with a compatible receiver. [Read more].
Hybrid Positioning
Hybrid Positioning actively uses elements from mutiple positioning technologies, such as GNSS and WiFi, to calculate a position. A typical example may be in indoor applications, where WiFi positioning information may be used to compensate for an insufficient number of visible satellites and ultimately render a position that is better than WiFi alone.
WiFi Positioning
WiFi positioning consists of recording the location of detected WiFi access points into a database. When the database is later queried by a device in the vicinity of previously detected access points, the position of the device may then be estimated. WiFi positioning augments GNSS positioning in areas where a GNSS receiver may not hear sufficient numbers of satellites to establish a fix. It is a useful technology for certain Location-Based Services, including indoors, but not an absolute replacement of GNSS due to lower accuracy and inconsistent coverage. Cellular positioning consists of recording the location of detected cellular towers into a database. When the database is later queried by a device in the vicinity of previously detected towers, the position of the device may then be estimated. Cellular positioning augments GNSS positioning in areas where a GNSS receiver may not hear sufficient numbers of satellites to establish a fix. It is a useful technology for certain Location-Based Services, including indoors, but not an absolute replacement of GNSS due to lower accuracy and inconsistent coverage. The accuracy of WiFi positioning may range from 30-250m and is especially dense in urban areas, but sparse elsewhere. Some vendors often refer WiFi positioning as hybrid positioning but in most cases, it is nothing more than an alternative to GNSS. True hybrid positioning actively uses information from multiple positioning technologies to render a position that is better than each technology on its own.