Indian Regional Navigational Satellite System
The Indian Regional Navigational Satellite System (IRNSS) is a planned domestically-produced satellite-based position, navigation, and timing (PNT) system under development by the Government of India. The government is concerned that it could be denied access to the US Global Positioning System (GPS) during emergencies or hostile situations. Like GPS, the IRNSS has been designed to operate in two modes: an open system for civilian use and a more accurate, encrypted system for military use. It differs from GPS, though, in only providing its planned service in the vicinity of the Indian subcontinent, India currently having no ambitions to expand into a global military power. The IRNSS will consist of a constellation of seven satellites, plus the ground support segment. Three satellites will be placed in geostationary orbits: one due south of central India (83°E) and two on either side of the first to the east (132°E) and west (34°E). Four other satellites will be placed in mid-level geosynchronous orbits, with two each crossing the equator at 55°E and at 111°E. The first satellite was launched into geostationary orbit on 1 July 2013. Earlier plans called for the system to be operational in 2014, but this has been pushed back to 2016. Later, two spare satellites may be placed in geosynchronous orbit to replace any of the four that may fail. Coverage of the IRNSS, when fully operational, will be the entire Indian subcontinent and waters of the Indian Ocean out to about 2,000 kilometers (1,200 miles) from India. Positioning accuracy of the civilian version of the system is expected to be less than 10 meters over the Indian subcontinent and less than 20 meters over the Indian Ocean. The system was developed by the Indian Space Research Organization (ISRO), located near Bangalore. A network of 21 ranging stations around the country will monitor the satellites for orbital location and accuracy of the navigation signal. Satellites are launched from the Satish Dhawan Space Centre on India’s east coast.