India's sixth navigation satellite, IRNSS-1F, placed in orbit

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The Indian Space Research Organisation (ISRO) has successfully launched India’s sixth navigation Indian Regional Navigational Satellite System (IRNSS) 1F satellite, moving a step closer to completing the satellite network for its own Regional Navigation Satellite System. 

The satellite was launched on-board India’s workhorse launch vehicle, the Polar Satellite Launch Vehicle (PSLV) from Satish Dhawan Space Centre (SHAR), Sriharikota in Andhra Pradesh. It was PLSV’s 34th mission.

The IRNSS-1F along with the navigation payload and ranging payload is also carrying a Rubidium atomic clock, which will transmit navigation service signals to users.  The signals will be available in one month. Function of the two payloads are :-

♦ Navigation payload : The navigation payload of IRNSS-1F will transmit navigation service signals and will operate in the L5 band and S band.

♦ Ranging payload : The ranging payload consists of a C-band transponder will facilitates accurate determination of the range of the satellites.

What is IRNSS 1F ?

⇒ IRNSS-1F is the sixth of seven satellites that would form a constellation of India's own navigation satellite network (IRNSS) . Other satellites of the series are- IRNSS-1A, IRNSS-1B, IRNSS-1C, IRNSS-1D and IRNSS-1E. 

⇒ It had a lift-off mass of 1,425 kg and was powered by two solar panels generating 1660 W and one Lithium-ion battery of 90 Ampere-hour capacity. It has a 12-year mission life. 

⇒ It will be placed in the Geosynchronous transfer orbit of the space. It will have apogee (farthest point to Earth) of  20,657 km and perigee (nearest point to Earth) of 284 km.

Indian Regional Navigation Satellite System :

The Indian Regional Navigation Satellite System or IRNSS is an indigenously developed Navigation Satellite System that is used to provide accurate real-time positioning and timing services over India and region extending to 1500 km around India.

The Indian Regional Navigation Satellite System (IRNSS) consists of a constellation of seven satellites of which 3 satellites will be placed in GEO orbit and 4 satellites will be placed in GSO orbit. approximately 36,000 km altitude above earth surface.

♦ Geosynchronous satellites:  The 4 geosynchronous satellites will be orbiting in pairs in two inclined geosynchronous orbits. When these satellites will be observed from the ground, these 2 pairs of satellites will appear to travel in figures of ‘8’. 

♦ Geostationary satellites:  The 3 geostationary satellites would be placed in the geostationary orbit over the equator. They match the Earth’s rotation and shall remain at a fixed position in the sky.

The IRNSS is similar to the global positioning system (GPS) of the US (24 satellites), Glonass of Russia, and Galileo of Europe, China's Beidou although other systems are global, the Indian system is regional in nature.

Costing : Each satellite costs around Rs. 150 crores while the PSLV-XL version rocket costs around Rs. 130 crores. The seven rockets would involve an outlay of around Rs. 910 crores.

Why we need our own satellite navigation systems ? 

Our own regional navigation systems holds crucial importance because access to foreign government-controlled global navigation satellite systems is not guaranteed in hostile situations and we faced such a situation during Kargil War in 1999, when Indian military needed GPS data for the region but US denied the access of Vital information through GPS so a need for an indigenous satellite navigation system was felt  so that we are not dependent on  foreign government-controlled global navigation satellite systems and our scientist have nearly achieved by developing Indian Regional Navigation Satellite System. 


♦ IRNSS is different from other navigational systems of the world as it comprises of only seven satellites while other similar systems in the world have more than 20 satellites.

♦ Once fully operational, the IRNSS will provide accurate position information service to users across the country and the region, extending up to an area of 1,500 km. It would be used for defence purposes as well.

♦ It would provide two types of services (i) Restricted Service (RS): an encrypted service provided to authorised users (ii) Standard Positioning Service (SPS): to all users.

Applications of  IRNSS : (a)  Visual and voice navigation for drivers (b)  Terrestrial navigation aid for hikers and travellers (c) Disaster Management (d) Terrestrial, Aerial and Marine Navigation .

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