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IRNSS · Programme history & context

NavIC

Why India built a regional navigation constellation, how the spacecraft were launched, what went wrong in orbit, and where to learn how GNSS works or read today's broadcast health.

LearnStatus
LearnHow GNSS works, animations and concepts.ConstellationEach satellite · live broadcast metrics.RAFSiRAFS hardware, how it works, and how it compares worldwide.StatusClocks, orbits, coverage, events from IGS data.
Operator / status
ISRO · Operational (regional)
Coverage
Regional PVT · primary disk ~1,500 km from borders
Cabinet approval
May 2006
Navigation centre
28 May 2013 · Byalalu, Karnataka
Launch attempts
12
Last launch
30 Oct 2026 (NVS‑03)
Nominal constellation
7 satellites
SPS accuracy (claimed)
~5–10 m on land (ISRO SPS claims); ~20 m in extended oceanic area
Programme cost
₹2,246 crore reported March 2017 (CAG); original 2006 estimate ~₹1,420 crore

Official PNT service needs at least four healthy navigation satellites. After IRNSS‑1F’s last clock failed (Mar 2026), only three count for PNT today: IRNSS‑1B, IRNSS‑1I, and NVS‑01 (one short of a NavIC‑only fix). On 2 Jul 2025, an RTI thread on X (indianspaceflight.in · solidbosters2) had listed four PNT spacecraft including 1F with one clock; that snapshot predates 1F’s final failure. NVS‑02 is excluded after its propulsion anomaly. NVS‑03 launched 30 Oct 2026 but was not yet commissioned for PNT while orbit‑raising continued. Our status dashboard uses the latest IGS merged navigation file for day‑to‑day broadcast health, not ISRO commissioning bulletins. Open status →

Atomic clock crisis · RTI & parliamentary reporting

NavIC needs at least four satellites for a standalone fix. IRNSS‑1F no longer contributes: all three rubidium clocks have failed. RTI reporting on 2 Jul 2025 (solidbosters2) described the fleet when 1F still had one clock; parliamentary answers echoed the wider Gen‑1 clock‑loss pattern.

Disclosed 2 Jul 2025 · solidbosters2 (founder, indianspaceflight.in): summarized from an RTI response on X. Thread on X →

  • PNT today (after 1F’s last clock failed, Mar 2026): IRNSS‑1B, IRNSS‑1I, and NVS‑01 only (three satellites), below the four‑sat minimum for standalone NavIC.
  • RTI snapshot (2 Jul 2025): counted four PNT spacecraft including IRNSS‑1F with 1 of 3 RAFS still working; that margin is gone after Mar 2026. NVS‑02 not counted, propulsion failure during orbit raise.
  • All three clocks failed on IRNSS‑1A, 1C, 1D, 1E, 1F, and 1G (Gen‑1 SpectraTime RAFS).
  • Gen‑1 spacecraft carry three imported rubidium clocks each; Gen‑2 NVS carries four RAFS per satellite (1 × iRAFS + 3 × imported), see the RAFS page.
  • IRNSS-1Ano

    Jul 2013 · RAFS 0 / 3

    All RAFS failed; messaging / legacy payload.

  • IRNSS-1Byes

    Apr 2014 · RAFS PNT active

    Operational PNT (2026 reporting).

  • IRNSS-1Cno

    Oct 2014 · RAFS 0 / 3

    All clocks failed; messaging.

  • IRNSS-1Dno

    Mar 2015 · RAFS 0 / 3

    All clocks failed; later decommissioned.

  • IRNSS-1Eno

    Jan 2016 · RAFS 0 / 3

    All clocks failed; messaging.

  • IRNSS-1Fno

    Mar 2016 · RAFS 0 / 3

    All RAFS failed; last clock Mar 2026. RTI Jul 2025 had reported 1 / 3.

  • IRNSS-1Gno

    Apr 2016 · RAFS 0 / 3

    All clocks failed; slot replaced by NVS‑01.

  • IRNSS-1Hlaunch failed

    Aug 2017 · RAFS n/a

    PSLV fairing failure.

  • IRNSS-1Iyes

    Apr 2018 · RAFS PNT active

    Replacement for 1A; RTI Jul 2025 PNT list.

  • NVS-01yes

    May 2023 · RAFS 4 (1 × iRAFS + 3 imported)

    Gen‑2; iRAFS driving navigation signals since Jul 2023.

  • NVS-02no

    Jan 2025 · RAFS 4 (1 × iRAFS + 3 imported)

    Not used for PNT, orbit‑raise propulsion fault.

  • NVS-03commissioning

    Oct 2026 · RAFS 4 (1 × iRAFS + 3 imported)

    Orbit raise to IGSO; not yet PNT operational.

Clock hardware and how iRAFS fits Gen‑2: RAFS page →

Why NavIC exists

During the 1999 Kargil conflict, Indian forces could not obtain GPS data for the theatre from the United States. Pilots reportedly used commercial GPS units to improve targeting, a dependency India did not want to repeat in a crisis.

NavIC (Navigation with Indian Constellation, formerly IRNSS) is ISRO’s autonomous regional system for position, velocity, and timing over India and about 1,500 km beyond the borders, with studies for extension toward 3,000 km.

The Union Cabinet approved the programme in May 2006. The design goal was Indian control of space, ground, and user segments, with seven satellites in geostationary and inclined geosynchronous slots so four or more stay visible over India.

NavIC offers Standard Position Service (SPS) open to civilians (interoperable with other GNSS where L1 is enabled on Gen‑2) and Restricted Service (RS) on encrypted channels for authorised users including the military.

Timeline

  1. 1999Kargil experience drives demand for an Indian-controlled navigation capability.
  2. 2006Union Cabinet approves IRNSS (~₹1,420 crore initial estimate).
  3. 2013ISRO Navigation Centre inaugurated at Byalalu; IRNSS‑1A launched on PSLV‑C22 (1 Jul).
  4. 2014IRNSS Signal-in-Space ICD released for evaluation (Sep).
  5. 2016IRNSS‑1G completes the planned seven-satellite Gen‑1 constellation (28 Apr).
  6. 2017IRNSS‑1H lost on PSLV‑C39 fairing failure (31 Aug).
  7. 2018IRNSS‑1I reaches orbit on PSLV‑C41 (12 Apr), replacing 1A for navigation.
  8. 2019AIS‑140 NavIC trackers compulsory on commercial vehicles in India (from 1 Apr).
  9. 2019US NDAA 2020 path to treat NavIC as allied navigation alongside Galileo and QZSS.
  10. 2023NVS‑01 (Gen‑2) on GSLV‑F12, L1 civil signal, iRAFS, replaces 1G slot (29 May).
  11. 2025NVS‑02 launched GSLV‑F15 but orbit‑raising failed (29 Jan).
  12. 2026NVS‑03 to transfer orbit on GSLV‑F18 (30 Oct); NVS‑04/05 reported in advanced fabrication.

Setbacks & gaps

Not every launch failed, PSLV placed the Gen‑1 string successfully. Operational and clock failures still shaped the usable constellation.

  • 2 Jul 2025

    RTI: four PNT satellites, zero clock margin (snapshot)

    An RTI response summarized on X by indianspaceflight.in founder solidbosters2 (2 Jul 2025) warned NavIC was at the four‑satellite edge: IRNSS‑1B, IRNSS‑1F (1 of 3 clocks), IRNSS‑1I, and NVS‑01. IRNSS‑1F is not counted for PNT on this page today: all three RAFS failed (last clock Mar 2026). Only IRNSS‑1B, IRNSS‑1I, and NVS‑01 remain for navigation. Later parliamentary answers and press reporting described the same Gen‑1 clock‑loss pattern.

  • 2016–2018

    Imported rubidium clocks failed across IRNSS‑1A and others

    SpectraTime clocks on IRNSS‑1A failed (2016), mirroring early Galileo clock issues. Multiple failures across the fleet followed; by 2018 nine of 24 orbiting clocks had failed per press reports. ISRO later ran some satellites on a single clock to preserve life.

  • 31 Aug 2017

    PSLV‑C39 / IRNSS‑1H launch failure

    The payload fairing did not separate on the fourth stage; IRNSS‑1H never reached the intended orbit. The spacecraft was meant to replace clock‑failed IRNSS‑1A.

  • 2018–2026

    Partial‑service satellites & decommissioning

    Several Gen‑1 birds lost all navigation clocks but remain useful for one‑way messaging (1A, 1C, 1E, 1F, 1G per parliamentary and ISRO reporting). IRNSS‑1D was decommissioned after its clocks failed.

  • 29 Jan 2025

    NVS‑02 propulsion anomaly

    GSLV‑F15 placed NVS‑02 in space, but orbit‑raising was disrupted by a valve malfunction. It is not operational for PNT, ISRO has looked at alternate uses; it did not replace IRNSS‑1E for navigation service.

  • 2023–2027

    Gen‑2 cadence & indigenous clocks

    NVS series needs GSLV and Indian Rubidium Atomic Frequency Standard (iRAFS) maturation. NVS‑04/05 and further slots were reported delayed by clock procurement and qualification. ISRO has discussed up to five clocks per future satellite after repeated failures.

Constellation slots

NavIC orbital slots over India: GEO at 32.5°E, 83°E and 129.5°E, IGSO pairs at 55°E and 111.75°E, with the satellites assigned to each
Every satellite assigned to each slot, past and present. NVS‑01 took over 129.5°E from IRNSS‑1G. NVS‑03, launched 30 Oct 2026, is raising its orbit to 32.5°E to replace IRNSS‑1F.

Space segment

  • Nominal design: 7 satellites, 3 in GEO (≈32.5°E, 83°E, 131.5°E) and 4 in inclined geosynchronous (IGSO) orbits (~55°E and ~111.75°E ground tracks).
  • Altitude ~35,786 km; dual-frequency legacy payload on Gen‑1 (L5 at 1176.45 MHz and S band ~2492 MHz).
  • Gen‑2 NVS adds interoperable L1 (1575.42 MHz) for phones and wearables; 12‑year design life vs 10 years on Gen‑1.
  • Messaging interface supports disaster and cyclone warnings to selected geographic areas (fisheries and coastal use cases).

Ground segment

  • IRNSS Spacecraft Control Facility (IRSCF) at Hassan and Bhopal, uplink, tracking, telemetry.
  • ISRO Navigation Centres at Byalalu (INC‑1) and Lucknow (INC‑2): redundancy for orbit & clock determination.
  • IRIMS ranging stations (16+ operational across India and partners; more planned e.g. Brunei, Australia, France, Japan).
  • IRNWT timing, NavIC system time reported to ~2 ns vs UTC (2σ) in ISRO documentation.
  • IRDCN links ground sites; laser ranging via ILRS partners; CDMA ranging at IRCDR stations.

Satellites · PNT vs messaging (reference)

Summarized from ISRO releases and open reporting. Live broadcast state: constellation page.

  • IRNSS-1Ano

    PRN I01

    Clocks failed; messaging / legacy payload use.

  • IRNSS-1Byes

    PRN I02

    Among satellites publicly cited for PNT in 2025–26 reporting.

  • IRNSS-1Cno

    PRN I03

    Clock failure; messaging service.

  • IRNSS-1Dno

    PRN I04

    Decommissioned after service life.

  • IRNSS-1Eno

    PRN I05

    Clock failure; messaging; NVS‑02 was intended replacement.

  • IRNSS-1Fno

    PRN I06

    All three RAFS failed (last clock stopped Mar 2026); messaging only. Jul 2025 RTI had counted it with one clock left.

  • IRNSS-1Gno

    PRN I07

    Superseded by NVS‑01 at 129.5°E; messaging.

  • IRNSS-1Hno

    PRN n/a

    Launch failed, fairing on PSLV‑C39.

  • IRNSS-1Iyes

    PRN I09

    Replacement for 1A; operational PNT in 2026 reporting.

  • NVS-01yes

    PRN I10

    L1+L5+S; iRAFS; replaced 1G.

  • NVS-02no

    PRN n/a

    Not in PNT service, propulsion fault during orbit raise (29 Jan 2025).

  • NVS-03commissioning

    PRN TBD

    GSLV‑F18 (30 Oct 2026). Not commissioned for PNT yet, still in orbit‑raising to ~111.75°E IGSO slot.

  • NVS-04 / 05planned

    PRN n/a

    Reported GSLV launches to restore four‑sat PNT margin.

Every launch

  • IRNSS-1Aorbit

    1 Jul 2013 · PSLV-XL-C22

    IGSO 55°E · clocks later failed

  • IRNSS-1Borbit

    4 Apr 2014 · PSLV-XL-C24

    IGSO 55°E

  • IRNSS-1Corbit

    16 Oct 2014 · PSLV-XL-C26

    GEO 83°E

  • IRNSS-1Dorbit

    28 Mar 2015 · PSLV-XL-C27

    IGSO 111.75°E · later decommissioned

  • IRNSS-1Eorbit

    20 Jan 2016 · PSLV-XL-C31

    IGSO 111.75°E

  • IRNSS-1Forbit

    10 Mar 2016 · PSLV-XL-C32

    GEO 32.5°E

  • IRNSS-1Gorbit

    28 Apr 2016 · PSLV-XL-C33

    GEO 129.5°E

  • IRNSS-1Hlaunch failed

    31 Aug 2017 · PSLV-XL-C39

    Fairing separation failure

  • IRNSS-1Iorbit

    12 Apr 2018 · PSLV-XL-C41

    Replacement for 1A

  • NVS-01orbit

    29 May 2023 · GSLV Mk II-F12

    GEO 129.5°E · Gen‑2

  • NVS-02orbit degraded

    29 Jan 2025 · GSLV Mk II-F15

    Orbit raise fault · not in PNT service

  • NVS-03orbit

    30 Oct 2026 · GSLV Mk II-F18

    IGSO 111.75°E · commissioning / orbit raise, not yet PNT operational

Gen‑1 vs Gen‑2

Gen‑1 (IRNSS‑1)

Orbit
3× GEO + 4× IGSO (29–31° incl.)
Signals
L5 (1176.45 MHz) · S band (~2492 MHz)
Clock
Imported rubidium (SpectraTime); 3 per satellite planned
Launches
PSLV‑XL · 2013–2018 (1H failed)
Design life
10‑year design

Gen‑2 (NVS)

Orbit
GEO / GTO → GEO or IGSO
Signals
L1 (1575.42 MHz) · L5 · S, L1 for civilian GNSS chips
Clock
4× RAFS per satellite: 1× indigenous RAFS (iRAFS) + 3× imported RAFS from SpectraTime/Orolia (Safran group)
Launches
GSLV Mk II · from 2023
Design life
12‑year design

Each NavIC Gen‑2 (NVS) satellite carries four rubidium atomic frequency standards (RAFS): one indigenous RAFS developed by ISRO/SAC and three additional RAFS units supplied by SpectraTime/Orolia, now part of Safran. RAFS page →

Civilian use & policy

  • Qualcomm–ISRO agreement (2019+) brought NavIC support into mobile chipsets; L1 on Gen‑2 targets mass‑market devices.
  • Defence Research and Development Organisation programmes for domestic NavIC timing chips and receivers.
  • Times dissemination: NavIC referenced for national time at NPL India (public reporting from 2025).
  • Future GINS / expanded NavIC: studies for 24‑sat MEO global layer and twelve‑sat MEO first phase in policy drafts, not yet operational.

Community & forum

Questions about NavIC coverage, phone chips, ISRO announcements, or how to read our dashboard, ask on the site forum. Search existing threads or start a new post.

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