NavIC

Also called: IRNSS, Navigation with Indian Constellation · Topic: Remote Sensing, GIS and GNSS · NCERT: Class 12, Ch 4 "Spatial Information Technology"

Meaning

NavIC (Navigation with Indian Constellation) is the operational name of the IRNSS (Indian Regional Navigation Satellite System). It is India's own satellite navigation system, built by ISRO. It gives position and time over India and up to 1,500 km beyond India's borders [2].

• It matters because India does not have to depend fully on GPS, which the US military runs.
• In a war or crisis, a foreign country could deny that service. NavIC gives India its own source of positioning, navigation and timing.

Explanation

How satellite navigation works (trilateration)

• GNSS (Global Navigation Satellite System): a group of satellites whose signals let a receiver on Earth find three things:
• Positioning: where it is (latitude, longitude, height).
• Navigation: how to get from one place to another.

• Timing: the exact time. Banks, power grids and phone networks depend on it.

• Trilateration (finding a position from distances, not angles):

• Each satellite sends a signal that says where the satellite is and the exact time the signal left.
• The receiver notes when the signal arrives. Travel time × speed of light = distance to that satellite.
• Three distances fix latitude, longitude and height.

• A fourth satellite corrects the error in the receiver's cheap quartz clock. So at least 4 satellites must be working.

• Why atomic clocks are the heart of the system:

• Radio signals travel at about 3,00,000 km per second.
• So a clock error of only 1 microsecond moves the position by about 300 m.
• If a satellite's atomic clock fails, it cannot help find positions. It can only send messages.

Design: 7 satellites in high orbits

• Planned constellation: 7 satellites [2].
• 3 in geostationary orbit (an orbit where the satellite seems to stay fixed above one point on the equator). They sit at 32.5°E, 83°E and 129.5°E [2].

• 4 in inclined geosynchronous orbit (IGSO) (the orbit takes 24 hours, like geostationary orbit, but is tilted). The tilt here is 29° to the equator. From the ground, each satellite traces a figure-of-eight over India [2].

• Why only 7 satellites are enough:

• All the satellites stay high over the Indian region all the time.
• So a regional system needs far fewer satellites than a global one, which needs 24 or more.

Signals, services and accuracy

• Accuracy:
• Position accurate to better than 20 m [2].

• Time accurate to better than 50 nanoseconds (2-sigma: true about 95% of the time) [2].

• Frequency bands:

• L5 at 1176.45 MHz and S band at 2498.028 MHz [2].

• A new civilian L1 signal at 1575.42 MHz [2]. GPS uses the L1 band too, so most phone chips can already receive it.

• Two services [2]:

• SPS (Standard Positioning Service): open to all civilians.

• RS (Restricted Service): encrypted (locked with a secret code), for strategic users such as the armed forces.

• NavIC works together with GPS, GLONASS, Galileo and BeiDou signals [2].

Problems and the NVS series (second generation)

• Clock failures:
• Atomic clocks failed on early satellites, so those satellites lost their positioning ability.

• IRNSS-1H failed in 2017, so it could not replace a satellite whose clocks had failed.

• Current status: In a reply to Parliament in July 2026, the government said only 3 satellites give positioning, navigation and timing services: IRNSS-1B, IRNSS-1I and NVS-01. Basic positioning needs at least 4 working satellites [4].

• NVS satellites: the second-generation NavIC satellites. They are meant to keep the service running and add new features [4].
• They carry an indigenous rubidium atomic clock (made in India). This lowers the risk of imported clocks failing.

• They add the L1 signal, so ordinary phones can use NavIC.

• Launch record:

• NVS-01: launched May 2023. It is working [4].
• NVS-02: launched 29 January 2025, but failed [3].
  • It stayed stuck in an elliptical transfer orbit (a temporary oval path before reaching the final orbit) of 170 × 37,785 km, tilted at 20.8° [3].
  • Cause: the firing signal did not reach the pyro valve (a small valve opened by a tiny explosive charge) on the oxidiser line of its engine. The most likely reason was a loose contact in a connector [3].
  • ISRO's Apex Committee asked for more backup in such valve systems. These fixes were used on CMS-03 (launched 2 November 2025) [3].
• NVS-03 is ready for launch. NVS-04 and NVS-05 are at an advanced stage of building. Five NVS satellites (NVS-01 to 05) are planned in all [4].

Where it occurs

• Coverage area: all of India plus a band up to 1,500 km beyond its borders [2]. This covers much of the Indian Ocean region and neighbouring countries.
• Geostationary slots: three satellites over the equator at 32.5°E, 83°E and 129.5°E [2].
• Who runs it: ISRO. IRNSS-1A, the first satellite, was launched in 2013. The system was renamed NavIC in 2016.
• At sea:
• The IMO (International Maritime Organization), the UN body for shipping, recognised NavIC in 2020. Ships can use it in the Indian Ocean region.

• NavIC sends safety-of-life alerts such as cyclone and tsunami warnings to fishermen far out at sea [2].

• On land: transport and vehicle tracking, location-based services, surveying and time signals [2].

• Other regional systems in the world: QZSS (Japan) covers Japan and the Asia-Oceania region. NavIC and QZSS are the two regional systems. GPS (USA), GLONASS (Russia), Galileo (EU) and BeiDou (China) are global.

Don't confuse with

• GPS: a global system owned by the US Government and run by the US military. Its satellites are in medium earth orbit at about 20,200 km, in 6 planes tilted at 55°, with a 12-hour orbit [8]. NavIC is regional and uses geostationary and IGSO satellites.
• GAGAN (GPS Aided GEO Augmented Navigation): not a separate navigation system. It is an SBAS (Satellite-Based Augmentation System) that corrects GPS errors for aircraft. It was built by ISRO and AAI and certified by the DGCA [2][5]. NavIC gives positions itself.
• CORS (Continuously Operating Reference Stations): fixed ground receivers run by the Survey of India, not ISRO. They give about ±3 cm accuracy with RTK (live correction from a nearby station) [6][7]. NavIC is satellite-based and accurate to better than 20 m.
• BeiDou: China's system started as regional but became global in 2020. NavIC is still regional.

Prelims Hooks

• NavIC = IRNSS, renamed in 2016. Design: 7 satellites = 3 geostationary (32.5°E, 83°E, 129.5°E) + 4 IGSO (29°) [2].
• Coverage: India + 1,500 km. Accuracy: better than 20 m for position and better than 50 nanoseconds for time [2].
• Bands: L5 and S band, plus a new L1 on NVS satellites so phones can receive it [2]. Services: SPS (civilian, open) and RS (encrypted, strategic) [2].
• Regional vs global: NavIC (India) and QZSS (Japan) are regional. GPS, GLONASS, Galileo and BeiDou are global.
• Status (July 2026): only 3 working satellites (IRNSS-1B, IRNSS-1I, NVS-01), below the minimum of 4 [4]. NVS-02 (January 2025) was stuck in transfer orbit because of a pyro-valve signal fault [3].
• Trap: NavIC was recognised by the IMO (shipping) in 2020, not by an aviation body. Aircraft approvals in India come from the DGCA.

Mains Points

• Strategic autonomy (GS-III, security): depending on GPS, which a foreign military controls, is risky. A country can lose the service at a key moment in a conflict.
• NavIC's encrypted Restricted Service gives India its own positioning and timing [2].

• But only 3 satellites are working against the 4 needed (July 2026), so the service depends on launching NVS-03 to NVS-05 quickly [4].

• Technology lessons (GS-III, science and technology):

• Imported atomic clocks failed → satellites lost their positioning ability → India built its own rubidium atomic clock for the NVS series [4].

• NVS-02 valve fault → more backup in valve firing, used on later missions such as CMS-03 [3].

• Disaster management and the blue economy (GS-III):

• NavIC sends cyclone and tsunami alerts to fishermen far out at sea, where mobile networks do not reach [2].
• This matters for India's long coastline. IMO recognition (2020) also lets ships use NavIC in the Indian Ocean region.

Related concepts

• Global navigation satellite system
• Global Positioning System
• Trilateration
• NVS series satellites
• GAGAN
• Continuously Operating Reference Stations

Read more

• Satellite navigation: GNSS, GPS, NavIC and GAGAN