Indian Space Research Organization(ISRO) has successfully put IRNSS 1G- seventh and the final satellite of the Indian Regional Navigation Satellite System (IRNSS) into a Sub-Geosynchronous Transfer Orbit (Sub-GTO). The final launch has thus given India, its own navigation system, christened by PM Modi as ‘NAVIC’.
The acronym expands to ‘Navigation With Indian Constellation’. On the launch, PM Modi said,
India is now proudly among five nations in the world which have established their own satellite navigation system. Until today, we were reliant on GPS and systems from other nations, but today we are independent.
The launch took place from Satish Dhawan Space Centre in Sriharikota at 12:50 PM IST via PSLV-C33. This was also the 35th flight for ISRO’s massively successful workhorse PSLV (Polar Satellite Launch Vehicle), by which previous six satellites were also put in their respective orbits.
IRNSS 1G is a 1425 Kg satellite which will complete the constellation of seven satellites constituting the regional navigation system of India- IRNSS. This will make sure India enters another elite space club — the one which has the likes of US, Russia, China and European Union possessing their own, indigenously developed navigation systems.
The previous satellites of this constellation, namely IRNSS 1A, IRNSS 1B, IRNSS 1C, IRNSS 1D, IRNSS 1E, and IRNSS 1F were launched in last two years beginning July 2013. Last two satellites, IRNSS 1E and IRNSS 1F were launched this year in January and March.
PM Modi further added,
This system has so much potential to be useful not only for the whole country, but also our neighbouring SAARC countries which are dependent on foreign systems and can now make use of this Indian system.
IRNSS 1G has the same configuration like its predecessors, carrying two types of payloads – navigation payload and ranging payload. The navigation payload of IRNSS-1G will transmit navigation service signals to users. This payload will be operating in L5-band and S-band.
A highly accurate Rubidium atomic clock is part of the navigation payload of the satellite. The ranging payload of IRNSS-1G consists of a C-band transponder which facilitates accurate determination of the range of the satellite.
According to an ISRO official, with the successful launch of the final satellite, over the next three to six months, all satellites would be stabilised as a constellation, their signals and performance verified and later put to use.
ISRO has also put two spare satellites ready on ground to be flown in an emergency. In addition to it, a full-fledged ground control centre in Bengaluru and tracking stations across the country have been put in place to complete the whole system.
IRNSS or NAVIC will offer two types of services, namely, Standard Positioning Service (SPS) which is provided to all the users and Restricted Service (RS), which is an encrypted service provided only to the authorised users.
The system is expected to provide a location accuracy of better than 20m (currently among the sharpest globally) to users in India as well as the entire region, extending up to 1500 km from its boundary. While the Government is terming this system as something developed for the purpose of better weather predictions for farmers and lake, the system could well provide to be more than just useful for the army as well.