The Indian Regional Navigation Satellite System constellation is now complete, with the Indian Space Research Organisation >successfully launching the seventh and final navigation satellite, IRNSS-1G . The first of the seven satellites >was launched in July 2013 . With this seventh launch, India has an independent regional navigation satellite capability that covers the entire country and an area extending about 1,500 sq. km beyond its border, with a position accuracy better than 20m in all weather conditions. The system will be operational in three to six months, once the satellites are stabilised as a constellation and initial tests are completed. Currently, the IRNSS does not have backup satellites in orbit that can be put to use in case of a glitch in any of the satellites. Two spare satellites are available for launch in case of an emergency. The navigation system will provide both Standard Positioning Services for civilian use and Restricted Services for military use. A navigation system can be achieved using a certain number of satellites for specific constellations. ISRO opted for seven satellites — three in geostationary and four (as two pairs) in geosynchronous orbits — to provide the best navigation services. The United States’s Global Positioning System has a constellation of at least 24 operational satellites and a network of ground stations across the world to provide coverage globally.
The U.S.’s GPS navigation system, which became operational in 1993, offers good coverage and service globally; other countries and regions already have or are building their own systems. Russia’s Global Navigation Satellite System too is global in coverage. In 2012, China got its BeiDou Navigation Satellite System operational, but unlike the GPS and Russia’s GLONASS, it is currently more regional in coverage; it intends to expand the system for global coverage by 2020. The European Satellite Navigation System, Galileo, with global coverage, will be operational only by 2019-2020. Japan too is establishing its own global system. With satellite positioning becoming the standard way of navigating and many civilian utilities reliant on it, the implications of signal failure, whether deliberate or accidental, will be enormous. More importantly, the availability of reliable, encrypted, accurate positioning and navigation information from IRNSS will mean that Indian military operations will not have to rely on GPS data. During normal times, the interoperability (where an instrument can receive signals from multiple systems of satellites) of IRNSS, GPS and GLONASS will mean that civilian users will have additional sources of data, especially in urban areas and mountainous regions. This will allow them greater accuracy in timing or position measurement. More services have come to rely on positioning and navigation information. As the IRNSS constellation becomes operational, the focus should shift to making sure that industry rises to the occasion to manufacture receivers. To begin with, smartphones sold in the country should be able to receive the IRNSS signal.
