GLObal NAvigational Satellite System is the Russian satellite navigation system, one of two existing and operational systems in the world. It allows determining position and velocity of objects at any point on Earth surface (including polar regions) and in near-Earth space.

Main operating principle of the system is determination of location by measuring distance between the object and points with known coordinates, i.e., satellites. Constellations of navigational spacecrafts are deployed on circular orbits with altitude of about 20000 km. Simultaneously, at every point on surface of Earth 4 to 16 navigational satellites deployed to orbit are "visible". Every satellite transmits signals and navigational equipment receives and processes them.

Distance is calculated by delay time of signal propagation between it being sent by a satellite and received by a navigational receiver antenna; To determine spatial coordinates in three dimensions, distance data to three satellites and system control time are necessary. Therefore for effective positioning signals from at least four satellites are used.

Orbital constellation's core of 24 satellites deployed in three orbital planes consists of "GLONASS-M" spacecrafts. New generation "GLONASS-K" spacecrafts flight tests have been initiated.

Project development is managed by the Russian Federal space agency (Roskosmos) and ОАО "Rossiyskie kosmicheskie sistemy", GLONASS principal organization.

System's chief designer is Yury Matevich Urlichich, general director and chief designer of ОАО "Rossiyskie kosmicheskie sistemy".

1976	Decree of the CC of CPSU and CM of the USSR No. 1043–361 dated 16.12.76 "on GLONASS navigation system development"
1982	First "GLONASS" spacecraft launch
1993	Operation testing of incomplete constellation has begun by Decree of RF President No. 658 RPS dated 24.09.1993.
1995	Operational constellation deployment by Decree of RF Government No. 237 dated 07.03.1995.
1986	Decree of the CC of CPSU and CM of the USSR on "GLONASS" spacecraft upgrading No. 136–46 dated 27.01.86.
1998	President's Instruction to RF Government on formation of a plan of preservation and development of GLONASS system
2001	Initiation of "Global navigation system" Federal special purpose program by Decree No. 587 dated 20.08.2001.
2003	First upgraded "GLONASS-M" spacecraft launch.
2008	spacecrafts constellation deployment
2011	New generation "GLONASS-K" spacecraft flight tests initiation.
2011	Operational 24 spacecrafts constellation deployment