Come this June, the Indian Space Research Organisation (ISRO) will launch IRNSS-1, the first of the seven Indian Regional Navigation Satellite System (IRNSS) GPS navigation satellites into orbit to provide real-time position, navigation and time services to multiple users, confirmed ISRO Chairman K Radhakrishnan earlier today. IRNSS-1 will be launched by ISRO’s PSLV-C22 launch vehicle from the spaceport at Sriharikota off the Bay of Bengal on Andhra Pradesh coast. ISRO plans to launch IRNSS-2 three months after in-orbit tests of the first one, and the remaining five satellites over a 14-month period by 2015. The IRNSS will have a space segment (constellation of satellites and signal-in-space), a ground segment and a user segment to provide multiple services on a 24 x 7 basis under all-weather conditions to a host of users. Three satellites will be placed in the geostationary equatorial orbit (GEO) at 34, 83 and 131.5 degree east and two satellites each in the geosynchronous orbit (GSO) with equator crossing at 55 and 111.5 degree east at an inclination of 29 degrees. The IRNSS will have two signals in L-5 and S-band on 1176.45MHz frequency and 2492.028MHz frequency with provision for down-links. The satellite constellation will provide two basic services—standard positioning service for civilian users (using the CA code) and restricted precision encrypted navigation service (Py code) for authorised (military) users. The navigation software has been indigenously developed in-house by ISRO.
Meanwhile, the country’s first 2,330kg dedicated military communications satellite—GSAT-7/INSAT-4F—is likely to be launched by Arianespace from Kourou, French Guyana, by this August. This is to be followed next year by the GSAT-7A communications satellite, also to be launched by Arianespace, for the Indian Air Force. Plans are also afoot to launch at least three additional remote-sensing satellites equipped with SAR antennae to add to the two already in orbit, these being the ISRO-developed RISAT-1 and the RISAT-2, which was built and delivered by Israel Aerospace Industries. These will be joined between 2016 and 2018 by the Cartosat-3 family of remote-sensing satellites that will offer imagery resolutions of 0.25 metres, and will replace the existing Cartosat-2, Cartosat-2A and Cartosat-2B satellites.