Isro to launch back-up satellite for NavIC navigation system

The Indian Space Research Organisation (Isro) will launch an eighth navigation satellite this month-end as a back-up for its 7-satellite constellation, which is now ready for the launch of an indigenous satellite navigation system.

Isro will launch the latest navigation satellite IRNSS-1H by the end of this month to augment the existing seven satellites of NavIC constellation.

To be launched on board PSLV-C39, IRNSS-1H will be a "back up" navigation satellite for IRNSS-1A, one among the seven satellites in the constellation, as its three rubidium atomic clocks on board had stopped functioning.

India's own GPS, called NavIC, is now a step closer to reality with Isro signing an MoU with the National Physical Laboratories (NPL) for time synchronisation, a process of aligning the working of the GPS with Indian Standard Time.

The spare or standby satellite will make up for the non-functioning of the three rubidium atomic clocks on board IRNSS-1A and one each in the other two NavIC satellites, IANS quoted Isro's Vikram Sarabhai Space Centre Director K Sivan as saying from Thiruvananthapuram.

Officials said The IRNSS-1A is functioning well but for its atomic clock and that there is no need to abandon the satellite, adding that there is only one atomic clock each in the other satellites.

The clocks provide precise locational data for the users. The first one was launched in July 2013 and the seventh one (IRNSS-1G) in April 2016.

Isro will be using a Polar Satellite Launch Vehicle (PSLV C39) with four strap-on motors to launch the satellite into a geo-transfer orbit. The satellite will be later transferred to a geo-stationary orbit, about 36,000 km above the earth, where the NavIC is orbiting over the last four years.

The launch authorisation board will decide on the date and time after all the checks were completed during the window for the launch schedule.

The NavIC system when operationalised will offer services like terrestrial and marine navigation, disaster management, vehicle tracking and fleet management, navigation aide for hikers and travellers, visual and voice navigation for drivers.

The Indian Regional Navigation Satellite System (IRNSS) is an independent regional navigation satellite system developed by India, which is on the lines of US-based GPS.

Prime Minister Narendra Modi has named the system 'NavIC' (Navigation with Indian Constellation).