Tech India's navigation satellites: Back on track

The successful launch of navigation satellite NVS-03 (in picture) from Sriharikota on November 1 achieves the critical objective of restoring India's homegrown satellite navigation constellation called NavIC. This system, providing position, navigation and timing (PNT) services across the country's landmass and up to 1,500 km beyond, had been handicapped after the 10-year-old satellite, IRNSS-1F, reached the end of its mission life in March with its onboard atomic clock ceasing to function. This meant that only three satellites, IRNSS-1B, IRNSS-1I and NVS-01, were available for PNT services though a minimum of four is required for optimal performance.

Hence, the NavIC constellation could not provide standalone positioning service though the timing service was functional.NavIC, earlier known as the Indian Regional Navigation Satellite System (IRNSS), was born out of a critical vulnerability during the Kargil war which prompted India to build an independent navigation satellite system to remove the dependence on foreign systems. It is one of only two regional navigation satellite systems in the world, the other being Japan's Quasi-Zenith Satellite System. NavIC's signals can provide user position accuracy of under 20 metres and timing accuracy of less than 50 nanoseconds, and it is interoperable with global navigation satellite systems.

But its ageing fleet and failing foreign-made atomic clocks had become a challenge after two satellites, IRNSS-1H in 2017 and NVS-02 in 2025, could not be placed into orbit.

NVS-03 is the third of a five-satellite series being developed to augment the NavIC constellation

. It carries an indigenous atomic clock, along with procured ones. Over the next 10 months, ISRO will launch two more navigation satellites, NVS-04 and NVS-05.- Ends