GLONASS

Róbert Adam

Introduction

GLONASS = Global navigation satellite system (Globalnaya Navigatsionnaya Sputnikovaya Sistema)

Radio-based satellite navigation operated for the Russian government by the Russian Space Forces

First flight tests in 1982 Optimal of 24 satellites in 1995 Since May 2007 free service for customers In October 2011 – full global coverage

Services

Standard Precision Service – Equivalent to Standard Positioning Service. Originally used L1 band but with modernization second civil signal L2 is transmitted. With first GLONASS-K the third band L3 is available for civilian users

High Precision Service – Equivalent for the Precise Positioning Service. Shares same carrier wave as the SP signal but with ten times bigger bandwidth. P-code never published by operators but it was made known to scientific community.

Space Segment

24 satellites distributed over three planes.

Ascending nodes are 120° apart. 8 satellites per plane with argument

of latitude displacement of 45° Operates on circular orbit with 19100

km altitude and inclination of 64.8° Time of orbit = 11 hours 15 minutes

GLONASS Constellation

Currently used satellites

GLONASS-M – 2nd generation. First launched in 2003. Provides feature of 2nd civil Band. Size is 2.4 m in diameter, 3.7 m in height with dual solar arrays of 7.2m. Its mass its about 1480 kg and lifetime about 2-3 years. Remarkable feature – addition of second band for civil signal.

GLONASS-K – 3rd generation. Lifetime of 10 years and weight reduced to 750 kg. Includes the CDMA for first time.

Ground Segment

The GLONASS Ground Segment is the responsible for the proper operation of the GLONASS system. GLONASS Control Segment monitors the status of satellites, Determines the ephemerides and satellite clock offsets and, twice a day, uploads the navigation data to the satellites.

Consists of: • System Control Centre • Five Telemetry, Tracking and Command centers • Central Clock • Three Upload Stations • Two Laser Ranging Stations • Four Monitoring and Measuring Stations • Six Additional Monitoring and Measuring Stations

User Segment

Consists of L-band radio receiver/processors and antennas which receive GLONASS signals, determine pseudo ranges and solve navigation equations.

GLONASS receiver is capable of determining user position, velocity and precise time by processing the signal broadcasted by satellites

Applications : Armed Forces, Communication and energy system synch, Geodesy, Cartography, Navigation, Animals monitoring

References

http://navipedia.net/index.php/Category:GLONASS

http://navipedia.net/index.php/GLONASS_Space_Segment

http://navipedia.net/index.php/GLONASS_General_Introduction

http://navipedia.net/index.php/GLONASS_User_Segment

http://navipedia.net/index.php/GLONASS_Ground_Segment

Thank you for your attention.