Indian Regional Navigational Satellite System
Encyclopedia
The Indian Regional Navigational Satellite System (IRNSS) is an autonomous regional satellite navigation system being developed by the Indian Space Research Organisation
which would be under total control of Indian government. The requirement of such a navigation system is driven by the fact that access to Global Navigation Satellite Systems, GPS, is not guaranteed in hostile situations.
A goal of complete Indian control has been stated, with the space segment, ground segment and user receivers all being built in India.
It is unclear if recent agreements with the Russian government to restore their GLONASS
system will supersede the IRNSS project or feed additional technical support to enable its completion. However reports came in Apr 2010 that India plans to start launching satellites by the end of 2011, at a rate of one satellite every six months. This means the IRNSS will be optimally functional by 2014. India also launched 3 new satellites into space to supplement this.
. These GEOs will be located at 34 East 83 East and 132 East longitude. The GSOs will be in orbits with a 24,000 km apogee and 250 km perigee inclined at 29 degrees. Two of the GSOs will cross the equator at 55 East and two at 111 East.
Such an arrangement would mean all seven satellites would have continuous radio visibility with Indian control stations. The satellite payloads would consist of atomic clocks and electronic equipment to generate the navigation signals.
According to a presentation by A Bhaskaranarayana to a meeting of COSPAR in Montreal on 15 July 2008, IRNSS signals will consist of a Special Positioning Service and a Precision Service. Both will be carried on L5 (1176.45 MHz) and S band (2492.08 MHz). The SPS signal will be modulated by a 1 MHz BPSK signal. The Precision Service will use BOC(5,2).
The navigation signals themselves would be transmitted in the S-band frequency (2–4 GHz) and broadcast through a phased array antenna to maintain required coverage and signal strength. The satellites would weigh approximately 1,330 kg and their solar panels generate 1,400 watts.
The System is intended to provide an absolute position accuracy of better than 20 meters throughout India
and within a region extending approximately 2,000 km around it.
The ground segment of IRNSS constellation would consist of a Master Control Center (MCC), ground stations to track and estimate the satellites' orbits and ensure the integrity of the network (IRIM), and additional ground stations to monitor the health of the satellites with the capability of issuing radio commands to the satellites (TT&C stations). The MCC would estimate and predict the position of all IRNSS satellites, calculate integrity, makes necessary ionospheric and clock corrections and run the navigation software. In pursuit of a highly independent system, an Indian standard time infrastructure would also be established.
Indian Space Research Organisation
The Indian Space Research Organisation is an independent Indian governmental agency established in 1969 for the research and development of vehicles and activities for the exploration of space within and outside of Earth’s atmosphere. Headquartered in Bangalore...
which would be under total control of Indian government. The requirement of such a navigation system is driven by the fact that access to Global Navigation Satellite Systems, GPS, is not guaranteed in hostile situations.
Development
The first satellite of the proposed constellation, developed at a cost of , is expected to be launched during 2012-2013 while the full constellation is planned to be realized around 2014.A goal of complete Indian control has been stated, with the space segment, ground segment and user receivers all being built in India.
It is unclear if recent agreements with the Russian government to restore their GLONASS
GLONASS
GLONASS , acronym for Globalnaya navigatsionnaya sputnikovaya sistema or Global Navigation Satellite System, is a radio-based satellite navigation system operated for the Russian government by the Russian Space Forces...
system will supersede the IRNSS project or feed additional technical support to enable its completion. However reports came in Apr 2010 that India plans to start launching satellites by the end of 2011, at a rate of one satellite every six months. This means the IRNSS will be optimally functional by 2014. India also launched 3 new satellites into space to supplement this.
Description
The proposed system would consist of a constellation of seven satellites and a support ground segment. Three of the satellites in the constellation will be placed in geostationary orbitGeostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
. These GEOs will be located at 34 East 83 East and 132 East longitude. The GSOs will be in orbits with a 24,000 km apogee and 250 km perigee inclined at 29 degrees. Two of the GSOs will cross the equator at 55 East and two at 111 East.
Such an arrangement would mean all seven satellites would have continuous radio visibility with Indian control stations. The satellite payloads would consist of atomic clocks and electronic equipment to generate the navigation signals.
According to a presentation by A Bhaskaranarayana to a meeting of COSPAR in Montreal on 15 July 2008, IRNSS signals will consist of a Special Positioning Service and a Precision Service. Both will be carried on L5 (1176.45 MHz) and S band (2492.08 MHz). The SPS signal will be modulated by a 1 MHz BPSK signal. The Precision Service will use BOC(5,2).
The navigation signals themselves would be transmitted in the S-band frequency (2–4 GHz) and broadcast through a phased array antenna to maintain required coverage and signal strength. The satellites would weigh approximately 1,330 kg and their solar panels generate 1,400 watts.
The System is intended to provide an absolute position accuracy of better than 20 meters throughout India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and within a region extending approximately 2,000 km around it.
The ground segment of IRNSS constellation would consist of a Master Control Center (MCC), ground stations to track and estimate the satellites' orbits and ensure the integrity of the network (IRIM), and additional ground stations to monitor the health of the satellites with the capability of issuing radio commands to the satellites (TT&C stations). The MCC would estimate and predict the position of all IRNSS satellites, calculate integrity, makes necessary ionospheric and clock corrections and run the navigation software. In pursuit of a highly independent system, an Indian standard time infrastructure would also be established.
Footnotes
- SATNAV Industry Meet 2006. ISRO Space India Newsletter. April - September 2006 Issue.
- http://www.rediff.com/news/2007/sep/27gps.htm
- Launch of first satellite for Indian Regional Navigation Satellite system next year The Hindu - Apr 10, 2010