GLONASS or "GLObal NAvigation Satelite System", is a space-based satelite navigation system operated by the Russian Aerospace Defence Forces. It provides an alternative to Global Positioning System (GPS) and is the second alternative navigational system in operation with global coverage and of comparable precision.
Manufacturers of GPS devices say that adding GLONASS made more satelites available to them, meaning positions can be fixed more quickly and accurately, especially in built-up areas where the view to some GPS satelites is obscured by buildings. Smartphones generally tend to use the same chipsets and since the versions used since 2015 receive GLONASS signals, smartphones using such chips receive GLONASS positioning information along with GPS.
GNSS positioning modules combines both systems GPS and GLONASS in order to increase the number of available satellites. This can allow GNSS modules to accelerate the Time-To-First-Fix and improve the accuracy of the position. Find more QUECTEL Products here.