NavIC: The Story of India's Own GPS

NavIC (Navigation with Indian Constellation) is India's regional satellite navigation system, built so India and the area 1,500 km around it need not depend on GPS. ISRO completed a seven-satellite constellation in 2016 — then imported atomic clocks began to fail, a replacement was lost on launch, and a second-generation satellite was stranded in 2025. This is how it is being rebuilt.

Every NavIC satellite ever launched, and the setbacks between them: 9 moments, and the story isn't finished.

9 milestones from 2013 to 2026: 6 successes, 2 failures, 1 partial successes and 0 other milestones.

2023–2026 · The second generation

The NVS series is heavier, launched on GSLV, and fixes the first generation's two weaknesses: it carries Indian-made atomic clocks, and it broadcasts on the L1 band that most smartphone chips already listen to.

NVS-03 · Heading for the fourth working slot

30 Oct 2026 · GSLV · Success

GSLV-F18 launched NVS-03 towards the 32.5° E slot. Once it arrives and is commissioned, NavIC will have four satellites providing navigation — the minimum for a position fix without help from GPS.

Comeback from NVS-02.

What went wrong: NVS-02 reached its transfer orbit but could not fire its own engine to climb to its slot.

Why: The command to open the oxidiser pyro valve never arrived — contacts in both the main and backup connector paths had most likely come loose.

What fixed it: ISRO added redundancy and checks to spacecraft pyro systems, first flown on CMS-03 in November 2025 and then on NVS-03.

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NVS-02 · Stranded after a perfect launch

29 Jan 2025 · GSLV · Rocket OK · satellite stranded

The 100th launch from Sriharikota placed NVS-02 in its transfer orbit, but the satellite's own engine never fired because the oxidiser valve did not open. It could not climb to its slot and is not part of the navigation service.

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NVS-01 · First Indian-made atomic clock in orbit

29 May 2023 · GSLV · Success · First indigenous atomic clock

GSLV-F12 launched the first second-generation NavIC satellite, weighing about 2,232 kg, into the 111.75° E slot. It is one of the three satellites providing navigation today.

Comeback from Atomic clocks start failing.

What went wrong: Imported atomic clocks failed on several first-generation satellites, leaving too few providing navigation.

Why: Faults in the imported rubidium clocks; ISRO has not published the detailed cause.

What fixed it: NVS-01 flew an indigenous rubidium atomic clock built by ISRO, and added the L1 frequency used by most phones.

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2016–2018 · Clocks fail, a replacement is lost

Within months of completion, the constellation's weakest part showed itself: imported atomic clocks. A satellite with no working clock can no longer help anyone find their position.

IRNSS-1I · Takes IRNSS-1A's place

12 Apr 2018 · PSLV · Success

PSLV-C41 launched the last first-generation satellite. It joined IRNSS-1B as one of the satellites still providing navigation today.

Comeback from IRNSS-1H.

What went wrong: IRNSS-1H, meant to replace the failed IRNSS-1A, stayed trapped inside PSLV-C39's heat shield.

Why: The payload fairing did not separate, so the satellite could not be released into orbit.

What fixed it: The second standby satellite, IRNSS-1I, launched on PSLV-C41 seven and a half months later and took over IRNSS-1A's slot.

IRNSS-1H · Replacement trapped in its rocket

31 Aug 2017 · PSLV · Failure

IRNSS-1H was launched to replace IRNSS-1A, but PSLV-C39's heat shield did not separate. The satellite never reached its orbit.

PSLV story

Atomic clocks start failing

2016–2017 · Failure

All three rubidium clocks on IRNSS-1A failed, reported in early 2017; clocks on other first-generation satellites later failed too. The clocks were imported, and a similar problem had hit Europe's Galileo satellites. ISRO has not published a detailed cause.

Satellites that lost their clocks were not wasted: they still relay short messages and disaster alerts, a service ISRO continues to run.

2013–2016 · Building the constellation

The plan was seven satellites: three in geostationary orbit over the equator and four in inclined geosynchronous orbits that trace figures-of-eight over India. Together they keep at least four satellites in view anywhere in the region — the minimum a receiver needs to work out its position.

IRNSS-1G completes the set — it's named NavIC

28 Apr 2016 · PSLV · Success · Constellation complete

PSLV-C33 launched the seventh and final satellite, completing the constellation. On the same day the Prime Minister named the system NavIC — Navigation with Indian Constellation; "navik" also means sailor or navigator in Hindi.

IRNSS-1B to 1F · Five more in two years

Apr 2014 – Mar 2016 · PSLV · Success

PSLV launched five more satellites in quick succession: IRNSS-1B (4 April 2014), 1C (16 October 2014), 1D (28 March 2015), 1E (20 January 2016) and 1F (10 March 2016). With four in orbit, the system could already compute positions over India.

IRNSS-1A · The first NavIC satellite

1 Jul 2013 · PSLV · Success · First Indian navigation satellite

PSLV-C22 launched IRNSS-1A, the first satellite of the Indian Regional Navigation Satellite System. Like all its first-generation siblings it carried three rubidium atomic clocks — the heart of any navigation satellite.

In the ISRO timeline

Key facts for exams

NavIC = Navigation with Indian Constellation; earlier IRNSS (Indian Regional Navigation Satellite System).
Coverage: India and about 1,500 km around it; planned constellation of 7 satellites (3 geostationary, 4 inclined geosynchronous).
First satellite IRNSS-1A launched 1 July 2013 on PSLV-C22; constellation completed by IRNSS-1G on 28 April 2016, when it was named NavIC.
IRNSS-1H was lost on PSLV-C39 (31 August 2017); IRNSS-1I (12 April 2018) replaced IRNSS-1A.
Second generation (NVS series) launches on GSLV: NVS-01 (29 May 2023) carried the first indigenous rubidium atomic clock and added the L1 band.
NVS-02 (29 January 2025) was stranded after its engine valve failed; NVS-03 launched 30 October 2026.

Words used on this page

Atomic clock: An extremely precise clock. Navigation satellites depend on them: a timing error of a millionth of a second puts your position off by about 300 metres.
Geostationary and geosynchronous orbit: An orbit about 36,000 km up that takes exactly one day, matching Earth's spin. A geostationary satellite sits over the equator and seems fixed in the sky; a geosynchronous one may drift north and south in a figure-of-eight.
Geosynchronous transfer orbit (GTO): A long oval orbit, low at one end and about 36,000 km at the other. Rockets drop communication satellites here; the satellite then fires its own engine at the high point to circle at that height.
NavIC (IRNSS) and the NVS satellites: India's own satellite navigation system, developed and operated by ISRO — an alternative to GPS over India and 1,500 km around it. The first-generation satellites are named IRNSS-1A to 1I; the second generation are NVS-01, NVS-02 and NVS-03.
Payload fairing: The nose cone that protects the satellite from air friction during the climb through the atmosphere, then splits open and falls away once the rocket is high enough.

Frequently asked questions

What is the full form of NavIC?

NavIC stands for Navigation with Indian Constellation. It was originally called IRNSS, the Indian Regional Navigation Satellite System, and was renamed when the seventh satellite completed the constellation on 28 April 2016.

How many NavIC satellites are there?

ISRO has launched 12 NavIC satellites: IRNSS-1A to 1I (1H was lost on launch) and NVS-01, NVS-02 and NVS-03. As of ISRO's 2025 list, three — IRNSS-1B, IRNSS-1I and NVS-01 — provide navigation, while satellites with failed clocks provide messaging. NVS-03 is meant to become the fourth navigation satellite.

Why did NavIC satellites fail?

Mostly because their imported rubidium atomic clocks failed, starting with all three on IRNSS-1A in 2016–17. A navigation satellite cannot give positions without an accurate clock. Separately, IRNSS-1H was lost when its rocket's heat shield did not separate, and NVS-02 was stranded when its engine valve did not open.

Is NavIC working right now?

For live status — which satellites are healthy and whether a NavIC-only position fix is possible — see our NavIC satellite tracker page, which is updated as satellites are launched or retired.