Global Positioning System (GPS) - United States of America
The system provides
critical capabilities to military, civil and commercial users around the world.
It is maintained by the United States government and is freely accessible to
anyone with a GPS receiver.The GPS project was developed in 1973 integrating ideas from several
predecessors, including a number of classified engineering design studies from
the 1960s. GPS was created and realized by the U.S. Department of Defense (DoD)
and was originally run with 24 satellites. It became fully operational in 1995. In 2000, the U.S. Congress authorized the modernization
effort, GPS III.The United States Air Force plans to purchase up to 32 GPS
III satellites. GPS IIIA-1, the first satellite in the series, was projected to
launch in 2014, but is now significantly delayed.
Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS) - Russia
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. Development of GLONASS began in
the Soviet Union in 1976. Beginning on 12 October 1982, numerous rocket
launches added satellites to the system until the constellation was completed
in 1995.GLONASS is the most expensive program of the Russian Federal Space
Agency, consuming a third of its budget in 2010. By 2010, GLONASS had achieved
100% coverage of Russia's territory and in October 2011, the full orbital
constellation of 24 satellites was restored, enabling full global coverage. The
GLONASS satellites' designs have undergone several upgrades, with the latest
version being GLONASS-K.
Global Navigation Satellite System (Galileo/GNSS)- European Union
Galileo is intended for civilian use only. The €5 billion
project is named after the Italian astronomer Galileo Galilei. The use of basic
(low-precision) Galileo services will be free and open to everyone. The
high-precision capabilities will be available for paying commercial users. Since 2012, the headquarters are
located in Prague's district of Holešovice. In operation Galileo will use two
ground operations centres, near Munich in Germany and in Fucino in Italy. On 21
October 2011 the first two of four operational satellites were launched to
validate the system. The next two followed on 12 October 2012, making it
"possible to test Galileo end-to-end". The first determination
of a position relying on signals emitted only from Galileo satellites was
achieved on 12 March 2013. On 22 August 2014, two more satellites were launched
from French Guiana but were injected into an incorrect orbit.
Indian
Regional Navigation Satellite System (IRNSS/SPS)- India
IRNSS is an autonomous regional satellite navigation system
being developed by the Indian Space Research Organisation (ISRO) which would be
under complete control of the Indian government. The IRNSS would provide two services, with the Standard
Positioning Service open for civilian use and the Restricted Service, encrypted
one, for authorised users (Military). As
part of the project, ISRO opened a new satellite navigation center within the
campus of ISRO Deep Space Network (DSN) at Byalalu near Bangalore in Karnataka
on 28 May 2013. A network of 21 ranging stations located across the country
will provide data for the orbit determination of the satellites and monitoring
of the navigation signal. India started
launching satellites by the end of 2011, at a rate of one satellite every six
months. This would have made the IRNSS functional by 2015.
BeiDou
Navigation Satellite System (BDS/COMPASS) - China
BeiDou Navigation Satellite System is a Chinese satellite
navigation system. It consists of two separate satellite constellations – a
limited test system that has been operating since 2000, and a full-scale global
navigation system that is currently under construction.The first BeiDou system,
officially called the BeiDou Satellite Navigation Experimental System and also
known as BeiDou-1, consists of three satellites and offers limited coverage and
applications. It has been offering navigation services, mainly for customers in
China and neighboring regions, since 2000.The second generation of the system,
officially called the BeiDou Satellite Navigation 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 as of January 2013. It is planned
to begin serving global customers upon its completion in 2020.
