ISRO successfully launches 7th navigation satellite IRNSS-1G

The seventh and final satellite of the Indian Regional Navigation Satellite System, the IRNSS 1G, was launched into a sub geosynchronous transfer orbit with a perigree (nearest point to earth) of 284 km and an apogee (farthest point to earth) of 20,657 km. The satellite was launched on board the Polar Satellite Launch Vehicle (PSLV), which took off from the Sriharikota launch pad.

With this launch, the IRNSS constellation of seven satellites is now complete. 

• This will allow the Indian Space Research Organisation (ISRO) to focus on the process of designing front end chips which will receive the navigational signals sent out by the satellites.
•  The system will be similar to the Global Positioning System (GPS) operated by the United States with 24 satellites and the Glonass, Galileo and BeiDou systems of Russia, Europe and China respectively.
• All satellites will undergo stabilisation testing and verification of their performance over the next few months before being pushed into use.
• An area of 1,500 km from Indian boundaries will be covered under the navigational system. 
• The Prime Minister invited other countries to make use of this system as well. “We have seven neighbours who rely on technology provided by other countries. 
• With an accuracy of better than 20 m being claimed by ISRO, the navigation system will be offered as an open or Standard Positioning Service and a superior, coded military Restricted Service.

Indian Regional Navigation Satellite System ( IRNSS ) :

• The Indian Regional Navigation Satellite System or IRNSS with an operational name of NAVIC (Navigation with Indian Constellation) is an Indian 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 fully deployed NAVIC system consists of 3 satellites in GEO orbit and 4 satellites in GSO orbit, approximately 36,000 km altitude above earth surface.
• However, the full system comprises nine satellites, including two on the ground as stand-by.
•  The requirement of such a navigation system is driven because access to foreign government-controlled global navigation satellite systems is not guaranteed in hostile situations, as happened to the Indian military depending on American GPS during the Kargil War.
•  The NAVIC would provide two services, with the Standard Positioning Service open for civilian use, and the Restricted Service (an encrypted one) for authorized users (including the military).
•  Once the NAVIC is declared operational after checking the systems – space (satellites), ground (ground stations) and the user-end signal receivers, India will formally join a select group of nations owning their own Navigational Satellite system .
• The NAVIC constellation of seven satellites are in orbit and is expected to operate from June 2016 onwards.

Seven satellites with the prefix "IRNSS-1" will constitute the space segment of the IRNSS.

1.  IRNSS-1A, the first of the seven satellites of the IRNSS constellation, was launched on 1 July 2013.
2.  IRNSS-1B was launched on 4 April 2014  on board the PSLV-C24 rocket. The satellite has been placed in geosynchronous orbit.
3.  IRNSS-1C was launched on 16 October 2014.
4.  IRNSS-1D on 28 March 2015
5. IRNSS-1E on 20 January 2016 
6. IRNSS-1F was launched on 10 March 2016
7.  and IRNSS-1G was launched on 28 April 2016.

By middle of 2016, India will have the full navigational satellite system in place.