Global Navigation Satellite Systems (GNSS)

A satellite navigation system with global coverage  and multi satellite platforms may be termed as  Global Navigation Satellite System (GNSS).

As of today the United States NAVSTAR Global  Positioning System (GPS), Russian GLONASS,  China’s COMPASS navigation system and  European Union’s GALILEO are global  operational GNSSs. GNSS is in initial deployment  phase, scheduled to be fully operational by 2020 at  the earliest.

Components of GNSS

1. NAVSTAR Global Positioning System (GPS)

The United States' NAVSTAR Global Positioning  System (GPS) consists of up to 31 medium Earth  orbit satellites in six different orbital planes, with  the exact number of satellites varying as older  satellites are retired and replaced. Operational  since 1978 and globally available since 1994, GPS  is currently the world's most utilized satellite  navigation system.

2. GLObal NAvigation Satellite System(GLONASS)

The formerly Soviet, and now Russian, Global  Navigation Satellite System (Global'naya  Navigatsionnaya Sputnikovaya Sistema), or  GLONASS, is a space based satellite navigation system  that provides a civilian radio navigation satellite service  and is also used by the Russian Aerospace Defense  Forces. The full orbital constellation of 24 GLONASS  satellites enables full global coverage.

3. Galileo positioning system (Galileo)

The European Union and European Space Agency  agreed in March 2002 to introduce their own alternative  to GPS, called the Galileo positioning system. The  system comprises of 30 medium earth orbiting  satellites. The first Galileo test satellite, the GIOVE-A,  was launched 28 December 2005, as of May 2016 the  system has 14 of 30 satellites in orbit. Galileo is  expected to be in full operational service in 2020.

4. BeiDou Navigation Satellite System (BDS)

The first Chinese BeiDou Navigation Satellite.

System known as BeiDou-1, consists of three satellites  since 2000 and offers limited coverage and applications.  The second generation of the system, officially called  the BeiDou Navigation Satellite System (BDS) and also  known as COMPASS or BeiDou-2, will be a global  satellite navigation system consisting of 35 satellites,  and is under construction and planned to begin serving  globally upon its completion in 2020.

Asian Regional Members to Join  the GNSS Club

The Indian Regional Navigation Satellite System (IRNSS)  with an operational name of NAVigation with Indian  Constellation (NAVIC) (meaning Sailor or navigator in Sanskrit & Hindi) is an autonomous regional satellite  navigation system which will be used to provide accurate  real-time positioning and timing services over India and the  region extending to 1,500 kilometers around India.

Japan’s Quasi-Zenith Satellite System (QZSS), is a  proposed three-satellite regional time transfer system and  the satellite-based augmentation system for the Global  Positioning System. The first satellite 'Michibiki' was  launched on 11 September 2010. Full operational status was  expected by 2018 after the expansion of the Quasi-Zenith Satellite System from three satellites to four.

Comparison of the Orbits of GNSS

Population Growth of GNSS

GNSS constellation 

• All Images were taken from the internet.
• All images are copyrighted by their original owners.