India's NavIC Already Tracks More Than 10,400 Locomotives and Serves Over 40,000 Fishing Boats, and NVS-03, the Satellite Meant to Restore Its Standalone Positioning, Is Ready for Launch

NavIC is the satellite navigation system ISRO built to give India its own position and time signals over the country and a belt 1,500 km around it. The Department of Space says real-time train tracking runs on more than 10,400 locomotives and that over 40,000 fishing vessels carry NavIC receivers. The design is seven satellites, and on 29 July 2026 the government told the Lok Sabha that three were giving navigation signals, one short of the four a receiver needs for a standalone fix, while the next satellite, NVS-03, was ready for launch.

Seven satellites in two kinds of orbit

A Department of Space reply in the Rajya Sabha on 4 August 2022 describes the layout. NavIC satellites sit in geostationary orbit, where a satellite hovers over one point on the equator, and in geosynchronous orbit, where the orbit is tilted and the satellite swings north and south of the equator each day. Both are about 36,000 km up. GPS satellites orbit at about 20,000 km, in what the reply calls medium Earth orbit.

ISRO’s launch notes give the details for two of them. IRNSS-1G was to be moved to a geostationary slot at 129.5 degrees East longitude. IRNSS-1I was headed for a geosynchronous orbit inclined 29 degrees to the equator, at 55 degrees East.

The satellites need a ground network. ISRO says the facilities for ranging, monitoring and generating navigation data are spread across 18 locations, and its Master Control Facility at Hassan in Karnataka took control of IRNSS-1G after launch.

Two signals, two services, one coverage zone

NavIC broadcasts in two frequency bands. The 2022 reply says two bands let a dual-frequency receiver correct for errors caused by the atmosphere.

ISRO describes two services. The Standard Positioning Service is open to everyone, and ISRO’s NVS-02 mission page gives its accuracy as better than 20 metres for position and better than 40 nanoseconds for time, both at 2 sigma. The Restricted Service is encrypted and open to authorised users only.

The primary service area is India plus the region up to 1,500 km beyond its boundary. An extended area runs to a rectangle spanning 30 degrees South to 50 degrees North and 30 to 130 degrees East. The 2022 reply says the zone was drawn around Indian territory and the 1,500 km margin because the system was conceived for critical national uses, including defence and commercial ones.

Why a position needs four satellites

A receiver solves for four unknowns: latitude, longitude, altitude and the error in its own clock. That is the same arithmetic GPS uses, which how GPS works and who owns it walks through. Girish Linganna, a space and defence analyst, put it to The Week as “Four unknowns demand four satellites.”

Three satellites can work only if the receiver already knows its altitude, The Week reports, and that guess can be badly off on mountain passes or in an aircraft.

How it compares with GPS

GPS is global and NavIC covers a region. GPS.gov, the US government’s site, says a smartphone is typically accurate to within 4.9 metres under open sky, a figure it attributes to the Institute of Navigation. It separately commits to a signal-in-space error of 2.0 metres or less, 95 percent of the time.

Those numbers are not measured the way ISRO’s 20 metres is, so they cannot be set side by side. The government’s own claim in 2022 was that NavIC is as good as GPS in position accuracy and availability within its service region.

In practice the two work together. The Department of Space’s reply of 29 July 2026 says the armed forces use multi-constellation navigation that includes NavIC, and that because most uses combine NavIC with other systems, users face no vulnerability. The Week reports that the NVS satellites add an L1 signal, the band ordinary GPS receivers already listen to, which could help NavIC reach phones and fitness trackers.

What it does today

The Department of Space’s 12 February 2026 reply lists over 10,400 locomotives with real-time tracking, over 40,000 fishing vessels with NavIC receivers for tracking and emergency alerts, and more than 60 phone models from global manufacturers that support NavIC. Its 10 December 2025 reply adds more than 140 certified vehicle-tracker models fitted in more than 15 lakh (1.5 million) public and commercial vehicles, and NavIC time receivers that carry Indian Standard Time to secondary clocks across the country.

NavIC also sends one-way messages. The 12 February reply says it broadcasts cyclone, tsunami and high-wave warnings, prepared with the Indian National Centre for Ocean Information Services, directly to receivers on boats, along with fishing-zone advisories and alerts about the international maritime boundary. For how the warnings themselves have changed over the years, see India’s cyclone deaths since 1999.

Two limits are on the record. The December 2025 reply says the government has not mandated NavIC and that discussions are ongoing. On aviation, the 25 March 2026 reply says talks with the Airports Authority of India on NavIC in air traffic management continue, and that India’s GAGAN augmentation system already serves air navigation.

Built in under three years, with a recurring clock problem

ISRO launched IRNSS-1A on 2 July 2013 and IRNSS-1G on 28 April 2016, which completed the seven-satellite constellation. After that launch Prime Minister Narendra Modi dedicated the system to the nation under the name NavIC, short for Navigation with Indian Constellation.

The atomic clocks have been the weak point. GPS World reported on 30 January 2017 that all three clocks on IRNSS-1A had failed, citing ISRO chairman A. S. Kiran Kumar in The Hindu. The satellite carried one primary and two back-up clocks. GPS World said the cause was not identified, and that Galileo satellites have had similar clock failures with rubidium clocks from the same Swiss maker, Spectratime.

The replacement, IRNSS-1H, was lost on 31 August 2017 when PSLV-C39’s heat shield failed to separate and the satellite was released still inside it, ISRO said. ISRO launched IRNSS-1I on PSLV-C41 on 12 April 2018.

The second generation began with NVS-01 on GSLV-F12 on 29 May 2023. ISRO’s page says it weighs about 2,232 kg, adds the L1 band and is the first satellite to carry an indigenous atomic clock.

Where the constellation stands in October 2026

IRNSS-1F, launched in March 2016, reached the end of its 10-year design life on 10 March 2026, ISRO says, and its onboard clock stopped on 13 March. The satellite stays in orbit for one-way messaging. The Department of Space’s 25 March reply counts 11 NavIC satellites launched and eight functional, three broadcasting navigation signals and five able to send one-way messages.

The 29 July reply names the three: IRNSS-1B, IRNSS-1I and NVS-01. It says the constellation cannot give standalone positioning but that timing is functional, and that NVS-04 and NVS-05 are in an advanced stage of realisation.

NVS-02, launched on 29 January 2025, was injected into a 170 by 37,785 km orbit at 20.8 degrees and could not raise itself to its working orbit. ISRO’s Apex Committee found that the drive signal never reached the pyro valve on the oxidiser line of its orbit-raising engine, most likely because at least one contact in each of the main and redundant paths of a connector came apart. ISRO says the fixes flew on the CMS-03 satellite, launched on LVM3-M5 on 2 November 2025, and its pyro systems performed satisfactorily.

The schedule has moved. In July 2025 the department said NVS-03 was planned by the end of 2025, with NVS-04 and NVS-05 at six-month gaps. The Week reported on 29 September 2026 that NVS-03 has been at Sriharikota since August, that the GSLV Mk II campaign began on 14 September with the first stage stacked, and that ISRO is aiming for mid-October. ISRO’s home page listed no launch date for it on 15 October 2026. The Week describes NVS-03 as broadcasting in L1, L5 and S bands with rubidium clocks that mix Indian-made and imported units.

The department’s 25 March 2026 roadmap lists completing the NavIC base layer constellation and inducting an indigenous space-grade atomic clock.