GLONASS: Russia's Global Navigation Satellite System – Science & Technology Notes

GLONASS is Russia's global navigation satellite system. It is the second alternate navigational system in use, with global coverage and comparable precision. It is operated by the Russian Aerospace Defence Forces. The GLONASS satellite constellation was launched in 1982 and became fully operational in 1993. In this article, we will discuss in detail regarding GLONASS which will be helpful for UPSC exam preparation.

What is GLONASS?

• The Global Orbiting Navigation System (GLONASS) is a radio-based satellite navigation system developed by the former Soviet Union and now operated by the Russian Space Forces on behalf of the Russian government.
• It is Russia's answer to the US Global Positioning System (GPS) and the European GALILEO system.
• GLONASS is comprised of 21 satellites plus three spares.
• The GLONASS satellites are in roughly circular orbits with nominal altitudes of 19,100 km and orbital periods of 11 hours, 15 minutes, 44 seconds.
• Because of the period value, it became possible to design a long-lasting orbital system that, unlike GPS, does not require correcting pulses during its active lifetime.
• The nominal inclination ensures global availability on Russian Federation territory even when several SVs are not operational.
• GLONASS development began in 1976, with the goal of achieving global coverage by 1991. Numerous satellite launches began in 1982 and continued until the constellation was completed in 1995.
• With the collapse of the Russian economy, the system quickly fell into disrepair after it was completed. Russia committed to restoring the system by 2011 beginning in 2001.
• GLONASS had achieved 100% coverage of Russia's territory by 2010, and the full orbital constellation of 24 satellites was restored in October 2011, enabling full global coverage.
• GLONASS satellite designs have been upgraded several times, with the most recent version being GLONASS-K.

Different Versions of GLONASS

• GLONASS - These satellites were launched in 1982 for military and government use. They were designed to measure weather, positioning, timing, and velocity.
• GLONASS-M satellites were launched in 2003 to add a second civil code, which is critical for GIS mapping receivers.
• GLONASS-K - In 2011, these satellites were launched to add a third civil frequency. There are three types: K1, K2, and KM.
• GLONASS-K2 satellites will be launched after 2015 (they are currently in the design phase).
• GLONASS-KM - These satellites will be launched after 2025 (research is currently underway).

GLONASS Satellites

Architecture of GLONASS

Space Segment (SS)

• The GLONASS Space Segment, according to the GLONASS Interface Control Document, is made up of 24 satellites in three orbital planes with ascending nodes 120 degrees apart.
• Eight satellites are evenly spaced in each plane, with a 45-degree latitude displacement argument.
• The satellites are in circular orbits at an altitude of 19100-km and an inclination of 64.8 degrees, with each satellite completing the orbit in about 11 hours 15 minutes.
• The satellite spacing allows for continuous and global coverage of the terrestrial surface and near-Earth space.

Ground Segment (CS)

• The GLONASS Ground Segment consists of the System Control Centre and a network of Command and Tracking Stations spread across Russia.
• The control segment monitors the status of the GLONASS constellation, corrects orbital parameters, and uploads navigation data.

User Segment (US)

• Finally, the GLONASS User Segment is made up of user receivers that calculate coordinates, velocity, and time from GLONASS navigation signals.

Applications of GLONASS

• SPS: The Standard Positioning Service (or Standard Accuracy Signal Service) is a free service available to all users worldwide.
• PPS: The Precise Positioning Service (also known as the High Accuracy Signal Service) is only available to the military and authorised users.
• It’s commercially used to transmit weather broadcasts, communications, navigation, and reconnaissance data.

Advantages of GLONASS

• When used alone, GLONASS does not have the same level of coverage as GPS, but when both are used together, accuracy and coverage are greatly improved.
• Since GLONASS was created by Russia, it is more useful in northern latitudes.
• GLONASS has an advantage in accuracy, with up to 2 metres of accuracy.
• GPS + GLONASS allows your device to be pinpointed by a network of 55 satellites located all over the world.
• When you are in an area where GPS signals are blocked, such as between large buildings or subways, you will be accurately tracked by GLONASS satellites.

Conclusion

Nowadays, GNSS technology applications are becoming increasingly diverse. To meet user needs, the GLONASS system and user navigation equipment must be continually improved. The GLONASS system development for the benefit of increasing user requirements and the system's competitiveness is largely determined by the capabilities of the GLONASS space segment.

FAQs

MCQs

Question: Global Navigation Satellite System (GLONASS) is operated by which of the following country?

(a) USA

(b) Russia

(c) China

(d) India

Question: What is the Galileo Project which has been in news recently? (UPSC 2007)

(a) An intercountry programme of missile shield developed by the United States of America

(b) A project developed by India with assistance from Canada

(c) An environmental protection project being developed by Japan

(d) A multi-satellite navigation project being developed by the European Union

Question: Which of the following pairs is/are correctly matched? (UPSC 2014)

Spacecraft Purpose

1) Cassini-Huygens: Orbiting the Venus and transmitting data to the Earth

2) Messenger: Mapping and investigating the Mercury

3) Voyager 1 and 2: Exploring the outer solar system

Select the correct answer using the code given below.

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3