Indian Regional Navigational Satellite System
|This article is outdated. (January 2013)|
|Indian Regional Navigational Satellite System|
IRNSS coverage area
|Type||Satellite navigation system|
|Accuracy||Less than 20 m over the Indian ocean region
Less than 10 m accuracy over main land India
|Coverage||1,500–2,000 kilometres (930–1,200 mi) around Indian landmass|
|Project Cost||16 billion (US$290 million)|
The Indian Regional Navigational Satellite System (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 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. 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).
The first satellite of the proposed constellation, developed at a cost of 16 billion (US$290 million), is expected to be launched during 2012–2013 while the full constellation is planned to be realised 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. Three satellites will be in geostationary orbit over the Indian Ocean. Missile targeting could be an important military application for the constellation.
Indian Regional Navigational Satellite System - IRNSS-1A, the first of the seven satellites of the IRNSS constellation, carries a Navigation payload and a C-band ranging transponder. The spacecraft employs an optimised I-1K structure with a power handling capability of around 1600W and a lift off mass of 1380 kg, and is designed for a nominal mission life of 7 years. IRNSS-1A is planned to be launched onboard PSLV-C22 in June 2013 while the full constellation is planned to be realised during 2014 time frame. 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 will make the IRNSS optimally functional by 2014. India also launched 3 new satellites into space to supplement this.
Indian Regional Navigational Satellite System (IRNSS-1) will be the first of the total seven satellites of the IRNSS constellation. It will have a lift off mass of 1380 kg and operate a navigation payload and a C-band ranging transponder and employ an optimised I-1K bus structure with a power handling capability of 1600W and is designed for a nominal mission life of 7 years. The satellite is being built at ISRO Satellite Centre, Bangalore. Dr.Nageswar Rao is the Project Director.
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 orbit. These GEOs will be located at 34 East 83 East and 132 East longitude. 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.
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 10 meters throughout Indian Landmass and better than 20 meters in the Indian ocean as well as a region extending approximately 2,000 km around India.
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.
See also 
- ^ SATNAV Industry Meet 2006. ISRO Space India Newsletter. April – September 2006 Issue.
- Launch of first satellite for Indian Regional Navigation Satellite system next year The Hindu – 10 Apr 2010
- K. Raghu (2007-09-05). "India to build a constellation of 7 navigation satellites by 2012". Livemint.com. Retrieved 2013-05-18.
- "India to develop its own version of GPS". Rediff.com. Retrieved 2010-12-30.
- "ISRO Forthcoming Satellite launches". isro.org. Retrieved 2011-09-24.
- "India Making Strides in Satellite Technology". Defence News. Retrieved 26 July 2012.
- "India to launch first navigational satellite on June 12". Zee news. May 18, 2013. Retrieved 2013-05-18.
- "India’s First Navigational Satellite IRNSS -1A to be Launched in June - International Business Times". Ibtimes.co.in. Retrieved 2013-05-18.
- S. Anandan (10 April 2010). "Launch of first satellite for Indian Regional Navigation Satellite system next year". Beta.thehindu.com. Retrieved 2010-12-30.
- H. Pathak. "3 Satellites To Be Launched By ISRO".
- "ISRO – Future programme". Isro.org. Retrieved 2013-05-18.
- "ISRO Forthcoming launches". Isro.org. Retrieved 2013-05-18.
- "First IRNSS satellite by December". Magazine article. Asian Surveying and Mapping. 5 May 2009. Retrieved 2009-05-05.
- A. Bhaskaranarayana Director SCP/FMO & Scientific Secretary Indian Space Research Organisation – Indian IRNSS and GAGAN