India built its own GPS, then its clocks began to die. Can NVS-03 bring NavIC back?

Who decides where you are?

Open the map on your phone and a blue dot tells you where you are. It comes from satellites in space.¹³

The same signals guide fishing boats and fleets of trucks, keep time for banks and power grids, and help track thousands of trains. The armed forces use them too.¹³⁴³

Most people never ask whose satellites those are. The best known system, GPS, belongs to the United States. A country that relies only on another country's satellites relies on that country keeping the signal on.¹⁷³

So India built its own. It is called NavIC, short for Navigation with Indian Constellation. It covers India and about 1,500 km around it. Anyone can use its open signal. A second, encrypted signal is reserved for authorised users.²⁶

ISRO Chairman V Narayanan calls it a strategic national asset that gives the country independent access to position, navigation and timing.⁸

How does a satellite know where you are?

Each navigation satellite is, at heart, a very precise clock that keeps broadcasting the time. Your phone compares the times from several satellites and works out how far it is from each one.¹³

That is why the clock matters so much. Radio signals travel about 300 metres in a millionth of a second, so a clock that drifts by that much moves your blue dot by that much.

And you need at least four working satellites to fix a position. Remember that number. Four.³

Then the clocks started to fail

In July 2017 the government told Parliament that ISRO had bought 27 rubidium atomic clocks from a foreign supplier for NavIC. All three clocks on the first satellite, IRNSS-1A, had misbehaved and been switched off.⁵

A replacement satellite was sent up. On 31 August 2017 its rocket flew normally except for one thing: the heat shield around the satellite did not come off. IRNSS-1H stayed trapped inside it.¹⁰¹¹

The next replacement, IRNSS-1I, finally reached space in April 2018. The government later said the clock fault had been traced to a component overheating, and that clocks on Europe's Galileo system had developed similar problems.¹²

The fix that got stuck

ISRO's answer was a new generation of satellites called NVS. The first, NVS-01, launched on 29 May 2023 with India's own rubidium atomic clock, built at the Space Applications Centre in Ahmedabad. ISRO says only a handful of countries have that technology.¹³

Then came NVS-02, on 29 January 2025. It was ISRO's 100th launch from Sriharikota, and the rocket did its job.¹⁴

The satellite did not.

To reach its working orbit it had to fire its own engine. The valves that feed the engine never opened. An ISRO committee traced the fault to a signal that never reached the valves, most likely a loose connector contact in both the main and the backup line. NVS-02 was stranded in the wrong orbit.¹⁴¹⁵

By July 2025 the count was stark. Eleven NavIC satellites launched. Four giving navigation services. Two never in their intended orbit.⁴

Down to three

Four is exactly the minimum, with no spare. On 13 March 2026 the last working atomic clock on IRNSS-1F, a satellite already past its ten year design life, stopped.⁷⁹

In July the government told the Lok Sabha what that meant. Only three satellites were giving position and timing. Four are needed. NavIC could not give a position on its own.³⁶

Phones did not go dark, because they combine NavIC with GPS and other systems. The government said the armed forces work the same way, so it saw no vulnerability. But the whole point of having your own system is not needing anyone else's, and for months India's could not do the job alone.³⁹

Four again

Late on 30 October 2026 a GSLV rocket lifted off from the second launch pad at Sriharikota carrying NVS-03. About 18 minutes later the satellite was in its transfer orbit.¹⁷

ISRO's Chairman said the constellation was restored to its minimum operational configuration of four satellites. Four. The number this story began with.⁸

It matters for the device in your pocket. Qualcomm said select chipsets would support NavIC's new L1 signal, and Apple's iPhone 15 Pro models listed NavIC support from September 2023.¹⁶¹⁷

So is it fixed?

Not yet. NVS-03 is in a transfer orbit, the same kind of stepping stone where NVS-02 got stuck. It still has to fire its engine and climb to its final slot before it can serve anyone.¹¹⁵

ISRO says the fixes recommended after NVS-02 were applied on a later satellite, CMS-03, launched in November 2025, and worked. NVS-03 is the first navigation satellite to face that test since.¹⁵

And four is the floor, not a comfortable margin. One more failure and NavIC is short again. The government said in July 2026 that the next two satellites, NVS-04 and NVS-05, were in an advanced stage of realisation.³