On 4 April 2014 at 17:14 IST, IRNSS-1B was launched. IRNSS-1B is the second out of seven in the Indian Regional Navigational Satellite System. We are inching closer to our own (self designed, tested and maintained) satellite navigation system and thus, we need not be dependent on the GPS services from USA or Russian GLONASS, henceforth. Does that statement sound orthodox to you? Well, during the Kargil war in 1999, India approached USA for the GPS data information to track the troops from Pakistan and USA denied upfront. That was the first time when Indians realized that they need their own navigation system to map and track the humongous span of mass and land, where India spreads across the globe.
The project IRNSS got approved in May, 2006 and if things had fallen as per plan, then we would have had a fully functional indigenous navigation system by now. But, being an engineer myself, I empathize with ISRO for the delay and appreciate the efforts being put by them in developing yet another successful space application.
What is the status? Well, before 1B, IRNSS-1A was launched in July 2013. The launch for IRNSS 1C and 1D has been scheduled by December, 2014. By the principle of triangulation, a minimum of four satellited are needed to accurately calculate a position (latitude, longitude and altitude) on a 3D plane. If things fall as per plan, by end of this year ISRO would have conducted the 3D position fixing test on IRNSS ground based receivers. By 2016, we should have all the 7 satellites launched and placed in their orbits.
What is the working of the system? 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.Three of the seven satellites will be in geostationary orbits and the other four in inclined geosynchronous orbits. From ground, the three geostationary satellites will appear at a fixed point in the sky. However, the four geosynchronous satellites moving in inclined orbits in pairs will appear to move in the figure of ‘8’ when ‘seen’ from ground. This is what has been shown in the image. The IRNSS design requirements call for a position accuracy of < 20 m throughout India and within the region of coverage extending about 1500 km beyond.
I feel lucky to be witnessing the birth of this technology in India. The fantasy of having an IRNSS app on the iOS for navigation services, is irresistible!