India’s NavIC satellite system faces challenge as IRNSS-1F failed after atomic clock malfunction: what we know

India’s indigenous GPS alternative, NavIC, has suffered setback with the loss of satellite IRNSS-1F after its final atomic clock stopped functioning on Friday.

With this development, only three satellites, IRNSS-1B, IRNSS-1L and NVS-01, remain operational for providing positioning, navigation and timing (PNT) services. This poses a challenge as a minimum of four satellites is reportedly required to ensure complete navigation coverage across India and surrounding areas.

“IRNSS-1F satellite launched in March 2016 has completed its design mission life of 10 years on 10th March 2026,” Indian Space Research Organisation (ISRO) stated on its website, adding, “On 13th March 2026, procured on-board Atomic clock stopped functioning. However, the satellite will continue to function in-orbit for various societal applications to provide one way broadcast messaging services.”

Since July 2013, the ISRO has launched 11 satellites for the nearly ₹2,250-crore NavIC navigation programme, but six of them have failed, largely due to defective imported atomic clocks in the initial phase and, in some recent cases, because of orbital complications, noted an Indian Express report.

‘11 satellites have been put in orbit’: Govt last year to Parl

In a reply tabled in Parliament last year, the Union government stated that only four of the 11 satellites deployed for the NavIC system were fully operational

for positioning, navigation and timing (PNT) services, while the remaining spacecraft were being utilised in a limited or sub-optimal capacity.

Minister of State for the PMO, Jitendra Singh informed the Lok Sabha on July 23 last year, stating, “As of now, 11 satellites have been put in orbit. Some of them are not functioning. At present, four satellites are providing Position, Navigation and Timing (PNT) services, four satellites are being used for one way message broadcast, one satellite got decommissioned after its end-of-life service. Two satellites could not reach the intended orbit.”

“Location services provided by the NavIC system in India are going to be affected,” the report cited space department sources as saying.

The government had further informed Parliament in its July 23 response that about 12,000 trains are planned to be tracked in real time using NavIC along with other Global Navigation Satellite System constellations, and that nearly 8,700 trains have already been equipped with NavIC-based tracking capability.

About NavIC

India experienced GPS denial, or reduced accuracy of navigation signals, during the 1999 conflict with Pakistan, which made it difficult for its armed forces to operate effectively in the challenging Himalayan terrain and limited their capacity to carry out precision strikes on enemy positions. Recognising this strategic weakness and dependence on foreign systems, the government decided to develop an indigenous alternative to the American GPS, reported WION.

While the United States operates GPS, China runs the BeiDou system, Europe manages Galileo, and Russia controls GLONASS, NavIC was conceived as India’s sovereign navigation network. Unlike these global services, NavIC has been designed to provide coverage primarily over the Indian subcontinent, extending up to about 1,500 kilometres beyond India’s borders.

Between 2013 and 2018, the ISRO launched the first generation of satellites under the Indian Regional Navigation Satellite System (IRNSS) programme, which was later renamed NavIC.