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Indian Regional Navigation Satellite System
Indian Regional Navigation Satellite System
Indian Regional Navigation Satellite System
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Navigation with Indian Constellation (NavIC)
Logo of NavIC
Country/ies of originIndia
OperatorISRO
TypeMilitary, Commercial
StatusOperational
CoverageRegional (up to 1,500 km or 930 mi from borders)
Accuracy3 m or 9.8 ft (public)
2 m or 6 ft 7 in (encrypted)
Constellation size
Nominal satellites7
Current usable satellites
List
  • IRNSS-

    1B/1F/1I (Operational)

    1A/1C/1D/1E/1G/1H (Clock failure, short-message services only, launch failure)

  • NVS-

    01/02 (Operational)

First launch1 July 2013; 12 years ago (1 July 2013)
Last launch29 January 2025
Total launches11
Orbital characteristics
Regime(s)geostationary orbit (GEO), inclined geosynchronous orbit (IGSO)
Orbital height35,786 km (22,236 mi)
Other details
Cost₹2,246 crore (US$266 million) as of March 2017[1]
Geodesy
Fundamentals
Concepts
Technologies
Standards (history)
NGVD 29 Sea Level Datum 1929
OSGB36 Ordnance Survey Great Britain 1936
SK-42 Systema Koordinat 1942 goda
ED50 European Datum 1950
SAD69 South American Datum 1969
GRS 80 Geodetic Reference System 1980
ISO 6709 Geographic point coord. 1983
NAD 83 North American Datum 1983
WGS 84 World Geodetic System 1984
NAVD 88 N. American Vertical Datum 1988
ETRS89 European Terrestrial Ref. Sys. 1989
GCJ-02 Chinese obfuscated datum 2002
Geo URI Internet link to a point 2010

Indian Regional Navigation Satellite System (IRNSS), with an operational name of NavIC (acronym for Navigation with Indian Constellation; also, nāvik 'sailor' or 'navigator' in Indian languages),[2] is an autonomous regional satellite navigation system that provides accurate real-time positioning and timing services.[3] It covers India and a region extending 1,500 km (930 mi) around it, with plans for further extension up to 3,000 km (1,900 mi).[4] An extended service area lies between the primary service area and a rectangle area enclosed by the 30th parallel south to the 50th parallel north and the 30th meridian east to the 130th meridian east, 1,500–6,000 km (930–3,730 mi) beyond borders where some of the NavIC satellites are visible but the position is not always computable with assured accuracy.[5] The system currently consists of a constellation of eight[6] satellites,[7][8] with two additional satellites on ground as stand-by.[9]

The constellation is in orbit as of 2018.[10][11][12][13] NavIC will provide two levels of service, the "standard positioning service", which will be open for civilian use, and a "restricted service" (an encrypted one) for authorised users (including the military).

NavIC-based trackers are compulsory on commercial vehicles in India,[14][15] and some consumer mobile phones with support for it have been available since the first half of 2020.[16][17][18][19][20]

There are plans to expand the NavIC system by increasing its constellation size from 7 to 11.[21]

Background

[edit]

The system was developed partly because access to foreign government-controlled global navigation satellite systems is not guaranteed in hostile situations, as happened to the Indian military in 1999 when the United States denied an Indian request for Global Positioning System (GPS) data for the Kargil region, which would have provided vital information.[22] The Indian government approved the project in May 2006.[23][24]

Developments

[edit]

First Generation (IRNSS series)

[edit]

As part of the project, the Indian Space Research Organisation (ISRO) opened a new satellite navigation centre within the campus of ISRO Deep Space Network (DSN) at Byalalu, Karnataka on 28 May 2013.[25] A network of 21 ranging stations located across the country will provide data for the orbital determination of the satellites and monitoring of the navigation signal.

A goal of complete Indian control has been stated, with the space segment, ground segment and user receivers all being built in India. Its location in low latitudes facilitates coverage with low-inclination satellites. Three satellites will be in geostationary orbit over the Indian Ocean. Missile targeting could be an important military application for the constellation.[26]

The total cost of the project was expected to be ₹14.2 billion (US$168 million), with the cost of the ground segment being ₹3 billion (US$35 million), each satellite costing ₹1.5 billion (US$18 million) and the PSLV-XL version rocket costing around ₹1.3 billion (US$15 million). The planned seven rockets would have involved an outlay of around ₹9.1 billion (US$108 million).[9][27][28]

The necessity for two replacement satellites, and PSLV-XL launches, has altered the original budget, with the Comptroller and Auditor General of India reporting costs (as of March 2017) of ₹22.46 billion (US$266 million).[1]

India's Department of Space in their 12th Five Year Plan (FYP) (2012–17) stated increasing the number of satellites in the constellation from 7 to 11 to extend coverage.[29] These additional four satellites will be made during 12th FYP and will be launched in the beginning of 13th FYP (2018–23) in geosynchronous orbit of 42° inclination.[30][31] Also, the development of space-qualified Indian made atomic clocks was initiated,[32] along with a study and development initiative for an all optical atomic clock (ultra stable for IRNSS and deep space communication).[33][29]

The NavIC Signal in Space ICD was released for evaluation in September 2014.[34]

From 1 April 2019, use of AIS 140 compliant NavIC-based vehicle tracking systems were made compulsory for all commercial vehicles in India.[14][15]

In December 2019, the United States Congress consented to designate NaVIC as one of their allied navigational satellite systems along with Galileo (Europe) and QZSS (Japan). The approval was as a part of National Defense Authorization Act 2020. The proposal was put forward by United States Secretary of Defense in consultation with Director of National Intelligence.[35][36]

Clock failure

[edit]

In 2017, it was announced that all three SpectraTime supplied rubidium atomic clocks on board IRNSS-1A had failed, mirroring similar failures in the European Union's Galileo constellation.[37][38] The first failure occurred in July 2016, followed soon after by the two other clocks on IRNSS-1A. This rendered the satellite non-functional and required replacement.[39] ISRO reported it had replaced the atomic clocks in the two standby satellites, IRNSS-1H and IRNSS-1I in June 2017.[21] The subsequent launch of IRNSS-1H, as a replacement for IRNSS-1A, was unsuccessful when PSLV-C39 mission failed on 31 August 2017.[21][40] The second standby satellite, IRNSS-1I, was successfully placed into orbit on 12 April 2018.[41]

In July 2017, it was reported that two more clocks in the navigational system had also started showing signs of abnormality, thereby taking the total number of failed clocks to five,[21] in May 2018 a failure of a further 4 clocks was reported, taking the count to 9 of the 24 in orbit.[42]

As a precaution to extend the operational life of navigation satellite, ISRO is running only one rubidium atomic clock instead of two in the remaining satellites.[21]

As of May 2023 only four first generation satellites were capable of providing navigation services[43] which is the minimum number required for service to remain operational.[44]

As of September 2024 only four satellites IRNSS-1B, IRNSS-1F, IRNSS-1I and NVS-01 were capable of providing navigation services.[45][46]

In July 2025, while responding to a query through Right to Information Act, the ISRO revealed that only five IRNSS satellites are completely defunct, having all of their three clocks failed. Meanwhile, one satellite has only one functional clock and only two satellites are fully functional.[47]

Indian Atomic clock

[edit]

In order to reduce the dependency on imported frequency standards ISRO's Space Applications Centre (SAC), Ahmedabad had been working on domestically designed and developed Rubidium based atomic clocks.[3][33][32][29] To overcome the clock failures on first generation navigation satellites and its subsequent impact on NavIC's position, navigation, and timing services, these new clocks would supplement the imported atomic clocks in next generation of navigation satellites.[48][49][50][51]

On 5 July 2017, ISRO and Israel Space Agency (ISA) signed an Memorandum of Understanding to collaborate on space qualifying a Rubidium Standard based on AccuBeat model AR133A and to test it on an ISRO satellite.[6]

The clocks are utilised by the NVS series of satellites.[24] As part of the Times Dissemination Project, which is overseen by the Ministry of Consumer Affairs, Food, and Public Distribution, NavIC will take the position of GPS as the reference time provider at the National Physical Laboratory of India from 2025.[52]

[edit]

In accordance with the range requirements for NavIC for both military and commercial applications, Defence Research and Development Organisation, through the Technology Development Fund scheme, has commissioned Accord Software and Systems, to build a tailored and flexible IRNSS Network Timing system domestically. Using NavIC data, the receiver chip will obtain and distribute Indian time for navigation. India currently depends on the US for this service.[53]

In 2020, Qualcomm launched four Snapdragon 4G chipsets and one 5G chipset with support for NavIC.[54][55] NavIC is planned to be available for civilian use in mobile devices, after Qualcomm and ISRO signed an agreement.[16][56] To increase compatibility with existing hardware, ISRO will add L1 band support. For strategic application, Long Code support is also coming.[57][58]

On December 7, 2023, Qualcomm revealed that select chipset platforms will enable NavIC L1 signals. The Qualcomm location suite, supports up to seven satellite constellations simultaneously and allows for faster Time to First Fix (TTFF) position acquisition for enhanced location-based services. It also makes use of all of NavIC's L1 and L5 signals for precise positioning. In the second half of 2024, Qualcomm chipset platforms will add further support for the NavIC L1 signals, and in the first half of 2025, commercial products that support the NavIC L1 signals should be available for sale.[59][60]

Time-frame

[edit]

In April 2010, it was reported that India plans to start launching satellites by the end of 2011, at a rate of one satellite every six months. This would have made NavIC functional by 2015. But the program was delayed,[61] and India also launched 3 new satellites to supplement this.[62]

Seven satellites with the prefix "IRNSS-1" will constitute the space segment of the IRNSS. IRNSS-1A, the first of the seven satellites, was launched on 1 July 2013.[63][64] IRNSS-1B was launched on 4 April 2014 on-board PSLV-C24 rocket. The satellite has been placed in geosynchronous orbit.[65] IRNSS-1C was launched on 16 October 2014,[66] IRNSS-1D on 28 March 2015,[67] IRNSS-1E on 20 January 2016,[68] IRNSS-1F on 10 March 2016 and IRNSS-1G was launched on 28 April 2016.[69]

The eighth satellite, IRNSS-1H, which was meant to replace IRNSS-1A, failed to deploy on 31 August 2017 as the heat shields failed to separate from the 4th stage of the rocket.[70] IRNSS-1I was launched on 12 April 2018 to replace it.[71][72]

System description

[edit]

The IRNSS system comprises a space segment and a support ground segment.

Space segment

[edit]

The constellation consists of 7 satellites. Three of the seven satellites are located in geostationary orbit (GEO) at longitudes 32.5° E, 83° E, and 131.5° E, approximately 36,000 km (22,000 mi) above Earth's surface. The remaining four satellites are in inclined geosynchronous orbit (GSO). Two of them cross the equator at 55° E and two at 111.75° E.[73][74][75]

Ground segment

[edit]

The ground segment is responsible for the maintenance and operation of the IRNSS constellation. The ground segment comprises:[73]

  • IRNSS Spacecraft Control Facility (IRSCF)
  • ISRO Navigation Centre (INC)
  • IRNSS Range and Integrity Monitoring Stations (IRIMS)
  • IRNSS Network Timing Centre (IRNWT)
  • IRNSS CDMA Ranging Stations (IRCDR)
  • Laser Ranging Stations
  • IRNSS Data Communication Network (IRDCN)
Rendering of an IRNSS Series 1 satellite

The IRSCF is operational at Master Control Facility (MCF), Hassan and Bhopal. The MCF uplinks navigation data and is used for tracking, telemetry and command functions.[76] Seven 7.2-metre (24 ft) FCA and two 11-metre (36 ft) FMA of IRSCF are currently operational for LEOP and on-orbit phases of IRNSS satellites.[73][77]

The INC established at Byalalu performs remote operations and data collection with all the ground stations. The ISRO Navigation Centers (INC) are operational at Byalalu, Bengaluru and Lucknow. INC1 (Byalalu) and INC2 (Lucknow) together provide seamless operations with redundancy.[78]

16 IRIMS are currently operational and are supporting IRNSS operations.[79] A few more are planned in Brunei, Indonesia, Australia, Russia, France and Japan.[80] CDMA ranging is being carried out by the four IRCDR stations on a regular basis for all the IRNSS satellites. The IRNWT has been established and is providing IRNSS system time with an accuracy of 2 ns (2.0×10−9 s) (2 sigma) with respect to UTC. Laser ranging is being carried out with the support of ILRS stations around the world. Navigation software is operational at INC since 1 Aug 2013. All the navigation parameters, such as satellite ephemeris, clock corrections, integrity parameters, and secondary parameters, such as iono-delay corrections, time offsets with respect to UTC and other GNSSes, almanac, text message, and earth orientation parameters, are generated and uploaded to the spacecraft automatically. The IRDCN has established terrestrial and VSAT links between the ground stations. As of March 2021, ISRO and JAXA are performing calibration and validation experiments for NavIC ground reference station in Japan.[81] ISRO is also under discussion with CNES for a NavIC ground reference station in France.[82] ISRO is planning a NavIC ground station at Cocos (Keeling) Islands and is in talks with the Australian Space Agency.[83]

Signal

[edit]

NavIC signals will consist of a Standard Positioning Service and a Restricted Service. Both will be carried on L5 (1176.45 MHz) and S band (2492.028 MHz).[84] The SPS signal will be modulated by a 1 MHz BPSK signal. The Restricted Service will use BOC(5,2). The navigation signals themselves would be transmitted in the L5 (1176.45 MHz) & S band (2492.028 MHz) frequencies and broadcast through a phased array antenna to maintain required coverage and signal strength. The satellites would weigh approximately 1,330 kg (2,930 lb) and their solar panels generate 1,400 W.

A messaging interface is embedded in the NavIC system. This feature allows the command center to send warnings to a specific geographic area. For example, fishermen using the system can be warned about a cyclone.[85]

Accuracy

[edit]

The Standard Positioning Service system is intended to provide an absolute position accuracy of about 5 to 10 metres throughout the Indian landmass and an accuracy of about 20 metres (66 ft) in the Indian Ocean as well as a region extending approximately 1,500 km (930 mi) around India.[86][87] GPS, for comparison, has a position accuracy of 5 m under ideal conditions.[88] However, unlike GPS, which is dependent only on L-band, NavIC has dual frequencies (S and L bands). When a low-frequency signal travels through atmosphere, its velocity changes due to atmospheric disturbances. GPS depends on an atmospheric model to assess frequency error, and it has to update this model from time to time to assess the exact error. In NavIC, the actual delay is assessed by measuring the difference in delay of the two frequencies (S and L bands). Therefore, NavIC is not dependent on any model to find the frequency error and can be more accurate than GPS.[89]

Future developments

[edit]

Second Generation (NVS series)

[edit]

ISRO will be launching five next generation satellite featuring new payloads and extended lifespan of 12 years. Five new satellites viz. NVS-01, NVS-02, NVS-03, NVS-04 and NVS-05 will supplement and augment the current constellation of satellites. The new satellites will feature the L5 and S band and introduces a new interoperable civil signal in the L1 band in the navigation payload and will use Indian Rubidium Atomic Frequency Standard (iRAFS.)[51][90][91][92] This introduction of the new L1 band will help facilitate NavIC proliferation in wearable smart and IoT devices featuring a low power navigation system. NVS-01 is a replacement for IRNSS-1G satellite and was launched on GSLV in 2023.[93][76][94]

ISRO has plans for a total of 7 NVS series satellites (including already launched NVS-1) for civilian navigation requirements. The IRNSS network is, as of November 2024, confined to strategic use by the Indian Armed Forces. They will be equipped with L1 band along with the L5 and S band. The system will provide an accuracy of 10 m (33 ft) within India, 20 m (66 ft) for the area surrounding India by 1,500 km (930 mi).[95][96]

Approved project cost of first five NVS satellites (NVS-01 to NVS-05) is ₹964.68 crore (equivalent to ₹10 billion or US$120 million in 2023) excluding the launch costs.[97]

As reported in August 2025, ISRO plans to launch at least three satellites by the end of 2026. However, the development of indigenous atomic clocks is an "element impeding the launch". The development is also being delayed since multiple components are needed to be imported which leads to procurement challenges. Following the multiple instances of atomic clock failures, five atomic clocks per satellite has been proposed for future units.[47]

Global Indian Navigation System

[edit]

Study and analysis for the Global Indian Navigation System (GINS) was initiated as part of the technology and policy initiatives in the 12th FYP (2012–17).[33] The system is supposed to have a constellation of 24 satellites, positioned 24,000 km (14,913 mi) above Earth. As of 2013, the statutory filing for frequency spectrum of GINS satellite orbits in international space, has been completed.[98] As per new 2021 draft policy,[99] ISRO and Department of Space (DoS) is working on expanding the coverage of NavIC from regional to global that will be independent of other such system currently operational namely GPS, GLONASS, BeiDou and Galileo while remaining interoperable and free for global public use.[100] ISRO has proposed to Government of India to expand the constellation for global coverage by initially placing twelve satellites in Medium Earth Orbit (MEO).[57]

List of satellites

[edit]

The constellation consists of 7 active satellites. Three of the seven satellites in constellation are located in geostationary orbit (GEO) and four are in inclined geosynchronous orbit (IGSO). All satellites launched or proposed for the system are as follows:

IRNSS series satellites

[edit]
IRNSS-1 series satellites[73][101]
Satellite SVN PRN Int. Sat. ID NORAD ID Launch Date Launch Vehicle Orbit Status Remarks
IRNSS-1A I001 I01 2013-034A 39199 1 July 2013 PSLV-XL-C22 Geosynchronous (IGSO) / 55°E, 29° inclined orbit Partial Failure Atomic clocks failed. The satellite is being used for NavIC's short message broadcast service.[78][102][103]
IRNSS-1B I002 I02 2014-017A 39635 4 April 2014 PSLV-XL-C24 Geosynchronous (IGSO) / 55°E, 29° inclined orbit Operational [104]
IRNSS-1C I003 I03 2014-061A 40269 16 October 2014 PSLV-XL-C26 Geostationary (GEO) / 83°E, 5° inclined orbit Partial Failure [46]
IRNSS-1D I004 I04 2015-018A 40547 28 March 2015 PSLV-XL-C27 Geosynchronous (IGSO) / 111.75°E, 31° inclined orbit Partial Failure [105][106][107]
IRNSS-1E I005 I05 2016-003A 41241 20 January 2016 PSLV-XL-C31 Geosynchronous (IGSO) / 111.75°E, 29° inclined orbit Partial Failure The satellite is being used for NavIC's short message broadcast service.[108][109][107]
IRNSS-1F I006 I06 2016-015A 41384 10 March 2016 PSLV-XL-C32 Geostationary (GEO) / 32.5°E, 5° inclined orbit Operational [110]
IRNSS-1G I007 I07 2016-027A 41469 28 April 2016 PSLV-XL-C33 Geostationary (GEO) / 129.5°E, 5.1° inclined orbit Partial Failure Replaced by NVS-01.Currently being used for NavIC's short message broadcast service.[76][109][107]
IRNSS-1H I008 I08 31 August 2017 PSLV-XL-C39 Geosynchronous (IGSO) / 55°E, 29° inclined orbit Launch Failed The payload fairing failed to separate and satellite could not reach the desired orbit.[70][111] It was meant to replace defunct IRNSS-1A.[102][21]
IRNSS-1I I009 I09 2018-035A 43286 12 April 2018 PSLV-XL-C41 Geosynchronous (IGSO) / 55°E, 29° inclined orbit Operational [41]
Animation of IRNSS
Around the Earth
Around the Earth - Polar view
Earth fixed frame - Equatorial view, front
Earth fixed frame - Equatorial view, side
Earth fixed frame - Polar view
   Earth ·   IRNSS-1B  ·   IRNSS-1C  ·   IRNSS-1E  ·   IRNSS-1F  ·   IRNSS-1G  ·   IRNSS-1I

NVS series satellite

[edit]
NVS series satellites[73][101]
Satellite SVN PRN Int. Sat. ID NORAD ID Launch Date Launch Vehicle Orbit Status Remarks
NVS-01 (IRNSS-1J) I010 I10 2023-076A 56759 29 May 2023[112][113] GSLV Mk II - F12[114] Geostationary (GEO) / 129.5°E, 5.1° inclined orbit Operational Replaced IRNSS-1G. Features extended lifespan, indigenous clock and new civilian band L1 for low power devices.[76][91][115]
NVS-02 (IRNSS-1K) 29 January 2025[116] GSLV Mk II - F15 Partial Failure Intended replacement of malfunctioning IRNSS-1E satellite.[117][118][119] However, NVS-02 suffered from a propulsion system failure and the ISRO is looking for alternative uses for the satellite.[120][121]
NVS-03 (IRNSS-1L) December 2025 GSLV Mk II-F17 Geosynchronous (IGSO), 32.5°E or 129.5°E, 29° inclined orbit Planned [122][123]
NVS-04 (IRNSS-IM) 2026 GSLV Mk II Geosynchronous (IGSO), 32.5°E or 129.5°E, 29° inclined orbit Planned [76][118][119]
NVS-05 (IRNSS-1N) 2026 GSLV Mk II Geosynchronous (IGSO), 32.5°E or 129.5°E, 29° inclined orbit Planned [76][118][119]

See also

[edit]

Other systems

[edit]
Main article: Satellite navigation

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Indian Regional Navigation Satellite System

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from Grokipedia
The Indian Regional Navigation Satellite System (IRNSS), now branded as NavIC (Navigation with Indian Constellation), is an independent regional system developed by the Indian Space Research Organisation () to deliver accurate positioning, navigation, and timing services over and an extended area up to 1,500 kilometers beyond its borders. The system comprises a constellation of seven satellites—three in geostationary orbits and four in geosynchronous orbits at approximately 36,000 kilometers altitude—supported by a ground segment including master control facilities and reference stations for continuous operation. Initial satellite launches began with IRNSS-1A on July 1, 2013, via PSLV-C22, culminating in full constellation deployment by April 2016 with IRNSS-1G, enabling two-tier services: a Standard Positioning Service for unrestricted civilian access and a Restricted Service for strategic applications with enhanced accuracy and security. Designed for position accuracy better than 20 meters across under all weather conditions, NavIC prioritizes regional self-reliance amid vulnerabilities in global systems like GPS, though early failures in satellites such as IRNSS-1A necessitated replacements and highlighted technical challenges in clock reliability. By 2025, multiple satellites had reached end-of-life or experienced failures, prompting to plan augmentations with newer navigation payloads on replacements like NVS series to sustain coverage and integrate dual-frequency L5 signals for improved performance in challenging environments.

Historical Development

Inception and Strategic Rationale

The development of the Indian Regional Navigation Satellite System (IRNSS), later branded as NavIC, stemmed from India's recognition of vulnerabilities in relying on foreign satellite navigation systems, particularly the U.S.-controlled (GPS). During the 1999 Kargil conflict with , Indian forces encountered degraded GPS accuracy due to U.S. selective availability policies and denial of precise military-grade signals, highlighting the risks of dependence on systems subject to geopolitical leverage and potential service interruptions. This experience underscored the strategic imperative for an indigenous system to ensure reliable positioning, navigation, and timing (PNT) services, especially for defense applications where foreign denial could compromise operational effectiveness. In response, the Indian government approved the on May 9, 2006, authorizing the establishment of a seven-satellite regional constellation capable of providing accurate PNT coverage over and up to 1,500 kilometers beyond its borders. The initiative, led by the , aimed to achieve by developing a sovereign navigation infrastructure insulated from external control or disruptions, thereby supporting both civilian and military needs without reliance on global systems like GPS. This push for reflected broader national priorities in space technology, prioritizing indigenous capabilities to mitigate risks in critical domains. From inception, IRNSS planning incorporated design features for enhanced robustness and precision, including dual-frequency transmissions in L5-band (centered at 1176.45 MHz) and S-band (centered at 2492.028 MHz) to enable direct ionospheric error correction and resistance to jamming, as S-band signals experience less atmospheric attenuation. Each satellite was equipped with atomic clocks to maintain high temporal accuracy essential for reliable pseudorange measurements and ephemeris data. These elements were selected to address limitations in single-frequency systems like GPS, ensuring operational resilience in India's equatorial ionospheric environment and potential adversarial scenarios.

Initial Constellation Buildout (2013–2016)

The buildout of the Indian Regional Navigation Satellite System (IRNSS) constellation commenced with the launch of IRNSS-1A on July 1, 2013, using the Polar Satellite Launch Vehicle (PSLV)-C22 in its XL configuration from the Satish Dhawan Space Centre at Sriharikota. This 1,425 kg satellite was placed into an inclined geosynchronous orbit, marking the first step toward establishing regional navigation coverage primarily over India and extending up to 1,500 km beyond its borders. Subsequent launches proceeded rapidly to deploy the remaining satellites in geosynchronous and geostationary orbits: IRNSS-1B on April 4, 2014, via PSLV-C24; IRNSS-1C on October 16, 2014, via PSLV-C26; IRNSS-1D on March 28, 2015, via PSLV-C27; IRNSS-1E on January 20, 2016, via PSLV-C31; IRNSS-1F on March 10, 2016, via PSLV-C32; and IRNSS-1G on April 28, 2016, via PSLV-C33. Each , weighing approximately 1,425 kg, carried payloads including highly accurate atomic clocks sourced from SpectraTime under a 2008 valued at €4 million, enabling onboard generation of precise timing signals for pseudorange measurements. This configuration allowed for real-time positioning computation independent of continuous ground-based corrections for basic operations. The completion of the seven-satellite constellation with IRNSS-1G's deployment achieved initial operational capability for IRNSS, later rebranded as NavIC. The system initiated services in the Standard Positioning Service (SPS), offering positioning accuracy of approximately 10 meters for civilian users, and the Restricted Service (RS) for authorized military and strategic applications with enhanced precision. These milestones demonstrated India's indigenous capability in deploying a functional regional satellite navigation architecture, leveraging proven launch reliability from the PSLV series to minimize deployment timelines.

Setbacks and Technical Hurdles (2017–2022)

The atomic clocks aboard IRNSS-1A, operational since its 2013 launch, suffered progressive failures that rendered the non-functional by early 2017, with the first clock malfunctioning in July 2016 and the remaining two failing shortly thereafter. These failures stemmed from issues in the imported clocks supplied by Spectratime of , compromising time synchronization essential for accuracy and highlighting vulnerabilities in the constellation's core timing infrastructure. By mid-2017, reports indicated malfunctions in four additional atomic clocks across other IRNSS satellites, further degrading system without fully incapacitating them, as each satellite carried three clocks with backups. In response, ISRO prioritized IRNSS-1H as a dedicated replacement for IRNSS-1A, incorporating enhanced thermal management to mitigate clock degradation risks observed in earlier models. However, on August 31, 2017, the PSLV-C39 launch of IRNSS-1H ended in failure when the —intended to separate approximately into ascent—remained attached to the fourth , trapping the 1,425 kg and preventing its injection into geosynchronous transfer orbit. Post-mission analysis attributed the anomaly to a likely malfunction in the pyro elements responsible for fairing separation, marking only the second PSLV failure after 41 flights and underscoring rare but critical ascent-phase reliability gaps in ISRO's . These setbacks exacerbated delays in achieving full operational redundancy for the seven-satellite constellation, as clock malfunctions propagated reliability concerns across the series, with analyzing failure modes linked to potential short circuits or testing procedures in the units. Efforts at 's to indigenize production encountered protracted development hurdles, including design iterations and qualification testing, perpetuating dependence on foreign-sourced components prone to premature degradation until corrective measures were incrementally applied in subsequent satellites like IRNSS-1I in 2018. By 2022, the cumulative impact left the system with partial functionality, as clock issues reduced effective coverage and prompted contingency reliance on ground-based augmentations, revealing causal limitations in scaling indigenous precision under operational constraints.

System Components

Space Segment

The space segment of the (IRNSS), operationalized as NavIC, comprises a constellation of seven satellites deployed in at an altitude of approximately 36,000 km to provide regional coverage over and surrounding areas extending up to 1,500 km. The architecture includes three satellites in (GEO) positioned at of 32.5° E, 83° E, and 131.5° E, ensuring fixed positions relative to the Earth's surface. Complementing these are four satellites in inclined (IGSO) with a 29° inclination to the ; two cross the at 55° E and the other two at 111.75° E, producing figure-eight ground tracks that enhance visibility and coverage over the region. Each IRNSS satellite features a lift-off mass of 1,425 kg and utilizes the I-1K platform, designed for a minimum operational life of 12 years. Power is supplied by two deployable solar arrays generating up to 1,660 W, supplemented by batteries to maintain functionality during orbital eclipses. The primary payloads consist of a transponder operating in L5 and S bands with for , alongside a CDMA ranging payload incorporating a C-band for satellite ranging support. Critical to the system's timing precision are the onboard atomic frequency standards (RAFS), with each equipped with three units: one primary and two redundants (hot and cold standby) to mitigate clock failures and ensure continuous high-accuracy time dissemination. A corner cube retroreflector array further enables precise laser ranging for . This hardware configuration prioritizes reliability through redundancies, tailored to the regional focus without global coverage ambitions.

Ground Segment

The ground segment of the Indian Regional Navigation Satellite System (IRNSS), operationalized as NavIC, encompasses terrestrial facilities responsible for satellite telemetry, tracking, command operations, orbit determination, signal monitoring, and navigation data uplink to maintain system-wide integrity and time synchronization. Central to this infrastructure is the Navigation Centre (INC), situated at the (IDSN) complex in Byalalu near Bengaluru, which processes ranging data, generates precise and clock corrections, and ensures synchronization with (UTC) through atomic clocks. Complementing the INC are the IRNSS Spacecraft Control Facilities (IRSCF) at the Facilities in , and , , which handle real-time satellite health monitoring, orbit raising post-launch, payload testing, and periodic uplinks of navigation parameters derived from ground-based predictions. A distributed network of IRNSS Range and Integrity Monitoring Stations (IRIMS), numbering around 15 and positioned at precisely surveyed sites across , performs continuous one-way ranging measurements to NavIC satellites, detects anomalies in pseudorange and carrier phase signals, and feeds data back to the INC for error modeling and broadcast corrections. For augmented precision, the segment incorporates IRNSS CDMA Ranging Stations (IRCDR) that execute two-way (CDMA) ranging to refine satellite-to-ground distance estimates, enabling differential NavIC capabilities that mitigate ionospheric and multipath errors in user positioning. An IRNSS Network Timing Centre, leveraging hydrogen masers and cesium clocks, provides the stable time reference disseminated across the network to align satellite onboard clocks with ground standards, supporting sub-meter accuracy in ranging operations.

Signal Specifications and Services

The Indian Regional Navigation Satellite System (IRNSS), also known as NavIC, transmits navigation signals primarily in the L5 band at 1176.45 MHz and the S-band at 2492.028 MHz, enabling dual-frequency operation to facilitate ionospheric error correction through differential ranging. These frequencies support (CDMA) modulation, where each satellite broadcasts a unique (PRN) code generated from with a length of chips, allowing receiver discrimination of signals from multiple satellites. NavIC provides two distinct service tiers: the Standard Positioning Service (SPS), which is openly accessible to civilian users via unencrypted signals on both L5 and S-bands, and the Restricted Service (RS), formerly referred to as Authorized Service, which employs encryption for secure access primarily by strategic and military users. The SPS signals include a data component modulated using binary offset carrier (BOC) schemes, such as BOC(1,1) for L5, to enhance tracking robustness, while RS incorporates additional message authentication and anti-spoofing features not available in SPS. Newer satellites in the NVS series introduce an L1 band signal at 1575.42 MHz for partial backward compatibility with GPS receivers, but the system's core architecture emphasizes indigenous L5 and S-band signals to maintain operational sovereignty independent of foreign constellations.

Accuracy Metrics and Performance

The Indian Regional Navigation Satellite System (IRNSS), also known as NavIC, is designed to deliver a position accuracy better than 20 meters (2σ) within its primary service area, encompassing and extending up to 1,500 kilometers around its borders. This specification applies to the Standard Positioning Service (SPS) using dual-frequency signals in L5 and S bands, with empirical tests confirming horizontal accuracies substantially exceeding this threshold under nominal conditions. For instance, in Q1 2021 monitoring across Indian regions, (CEP, 50% probability) values ranged from 1.77 meters to 3.30 meters, derived from analyses of user equivalent range error (URE) and dilution of precision (DOP) metrics.
RegionJanuary CEP (m)February CEP (m)March CEP (m)
Southern2.041.772.11
Western2.292.542.44
Central1.982.011.98
Northern1.982.192.14
Eastern2.893.303.17
Real-world single-point positioning (SPP) tests using NavIC L5 signals alone have yielded 2D root mean square error (2DRMS) values of approximately 5.1 meters for high-end ISRO-IGS receivers, with CEP around 2.1 meters, based on seven-day data collections in eastern . These results reflect stability and low ionospheric scintillation impacts in the primary area, though performance can degrade to tens of meters during periods of reduced or uncorrected clock drifts, as observed in historical assessments. Beyond the primary service area, accuracy deteriorates markedly due to poorer geometric dilution of precision (GDOP) from the geostationary (GEO) and geosynchronous (GSO) orbital configuration, often exceeding 100 meters without differential augmentation, limiting utility for extended regional applications. In comparison to GPS, which achieves civilian accuracies of 5–10 meters globally via (MEO) satellites, NavIC's regional focus constrains worldwide performance but confers advantages in jamming resistance; its S-band signals and high-elevation GEO/GSO geometry reduce vulnerability to ground-based interference, as zenith-directed transmissions maintain stronger signal-to-noise ratios against low-angle jammers.

Operational Status and Challenges

Current Satellite Constellation

As of October 2025, the NavIC constellation maintains partial operational capability with five fully functional satellites: IRNSS-1B, IRNSS-1C, IRNSS-1F, IRNSS-1I, and NVS-01. These , positioned in geosynchronous and geostationary orbits, deliver standard positioning service (SPS) and restricted service (RS) signals for over and up to 1,500 km beyond its borders. Of the eight satellites successfully injected into orbit since the program's inception, the others—IRNSS-1A, IRNSS-1D, and IRNSS-1G—ceased operations due to failures in the first two and power subsystem anomalies in the latter. NVS-01, the inaugural second-generation satellite launched on May 29, 2023, via GSLV-F12, incorporates an indigenous rubidium atomic clock alongside compatibility for L1 band signals, bolstering the system's resilience against prior clock-related vulnerabilities. The subsequent , deployed on January 29, 2025, aboard GSLV-F15, encountered a critical malfunction shortly after reaching , stranding it in an elliptical path and restricting signal transmission to 2-3 hours daily with suboptimal coverage. Regional navigation reliability persists through hybrid GPS-NavIC , which compensates for gaps in pure NavIC , though standalone system exhibits owing to the diminished constellation size.

Reliability and Failure Analysis

The Indian Regional Navigation Satellite System (IRNSS), also known as NavIC, has encountered significant reliability challenges primarily stemming from premature failures of its rubidium atomic frequency standard (RAFS) clocks, which are critical for maintaining precise timing and positioning accuracy. IRNSS-1A, launched on July 1, 2013, saw all three onboard clocks fail by early 2017—starting with one in mid-2016 and followed by the backups—falling far short of the 12-year design life. These failures were linked to probable short-circuiting within the clock assemblies, highlighting vulnerabilities in the components sourced from Spectratime of , though later incorporated modified clock designs to address observed degradation patterns. Such clock malfunctions have recurred across the constellation; as of August 2025, five of the eleven launched satellites had experienced failures, including IRNSS-1F, where two of three clocks ceased functioning, rendering the system perilously close to a total timing breakdown per Right to Information disclosures. These issues, often manifesting years ahead of expected operational lifespan, underscore inadequacies in component resilience to the , including radiation-induced anomalies that erode clock stability beyond terrestrial testing thresholds. Consequently, over half the constellation was degraded or non-operational by mid-2025, with satellites like IRNSS-1B exceeding its 10-year lifespan amid ongoing risks and IRNSS-1F approaching critical failure thresholds. External factors have compounded these hardware vulnerabilities, notably during the intense of May 10-11, 2024—the strongest since 2003, with a Dst index of -412 nT—triggered by multiple coronal mass ejections. Observations using IRNSS/NavIC signals revealed pronounced F-region ionospheric disturbances over , including enhanced scintillation and total electron content (TEC) irregularities that amplified positioning errors by factors of 1.5 to 5 times under nominal conditions. These perturbations, rooted in solar wind-magnetosphere-ionosphere coupling, exposed the system's sensitivity to events, where baseline clock and signal instabilities were exacerbated, leading to degraded service reliability during peak disturbances.

Strategic Dependencies and Limitations

Despite assertions of technological self-reliance under India's framework, the Indian Regional Navigation Satellite System (IRNSS, operationalized as NavIC) maintains significant dependencies on imported components, particularly in its technology. The original IRNSS-1 series satellites, launched between 2013 and 2016, each incorporated three procured from the Swiss firm SpectraTime, exposing the system to foreign risks and potential geopolitical leverage in maintenance or upgrades. Indigenization efforts for clocks, initiated to address these vulnerabilities, have encountered substantial delays, stalling ISRO's planned launches of replacement satellites such as the NVS series, with only partial progress achieved by mid-2025. NavIC's regional coverage, limited to approximately 1,500 km around the , necessitates fallback to the U.S.-controlled (GPS) for broader applications, undermining claims of full navigational sovereignty. This hybrid dependency persists in civilian, commercial, and contexts, where seamless global positioning remains unattainable without GPS augmentation. In potential conflicts, U.S. authorities retain the capacity to selectively deny or degrade —as demonstrated during the 1999 , which prompted IRNSS development—leaving Indian systems partially exposed despite NavIC's existence, as regional signals alone cannot substitute for denied global coverage. A Right to Information (RTI) disclosure in 2025 highlighted these frailties, revealing that five IRNSS satellites had become fully defunct due to total failures, reducing the operational constellation to just four satellites capable of providing services. This operational shortfall, amid an initial project investment exceeding ₹1,420 crore approved in , has drawn criticism for inefficient resource allocation and delayed self-sufficiency, as redundant foreign-sourced clocks failed prematurely without adequate indigenous backups. Such revelations question the system's wartime readiness and long-term viability, given the causal link between clock reliability and positional accuracy in GNSS architectures.

Applications and Impacts

Civilian and Commercial Adoption

The Indian government mandated NavIC receiver support in all 5G smartphones sold in the country starting January 1, 2025, with non-5G models required to comply by December 2025, as announced by the Ministry of Electronics and Information Technology to foster self-reliance in positioning technologies. Chipmakers like Qualcomm have facilitated this through Snapdragon series processors, which have included NavIC compatibility since late 2019 and added full L1 and L5 signal support in select platforms from the second half of 2024 onward, enabling hybrid augmentation with GPS for improved regional accuracy in consumer devices. Despite these integrations, primary reliance on NavIC signals alone remains minimal in smartphones, with most devices defaulting to GPS hybrids due to NavIC's regional constraints and the absence of widespread software prioritization for standalone operation as of October 2025. In fisheries, NavIC supports vessel monitoring through transponders linked to the Vessel Communication and Safety System, with initiatives to equip 100,000 fishing boats by late 2024 for real-time tracking and alerts in high seas, enhancing safety via ISRO's satellite messaging. Disaster management applications leverage NavIC for early warnings on cyclones, floods, and earthquakes, with service expansions announced in August 2025 to disseminate location-specific alerts independent of ground infrastructure. Agricultural uses include NavIC-enabled tools for precision irrigation, soil mapping, and yield optimization, deployed via government-backed schemes that integrate satellite data for farmer advisories on weather and crop health. Standalone NavIC positioning, while achieving 5-10 meter accuracy within its primary service area, faces limitations in signal availability and multipath errors outside the region, leading to hybrid modes dominating commercial implementations over pure NavIC reliance. Penetration in infrastructure remains low, constrained by these performance gaps and the entrenched ecosystem of global GNSS, though mandates and initiatives are driving gradual uptake in targeted sectors like rural mobility and .

Military and National Security Uses

The Restricted Service (RS) of NavIC, utilizing encrypted S-band and L5 signals, supports operations including guidance for precision-guided munitions, real-time troop and vehicle , and enhanced through high-accuracy positioning. This service enables sub-meter accuracy for targeting in restricted scenarios, distinct from the civilian Standard Positioning Service. NavIC's military efficacy was demonstrated during Operation in May , where it provided geolocation data for strikes, navigation, drone operations, and ground force movements against terrorist targets in Pakistan-administered regions, achieving precision impacts without reliance on foreign GNSS. The system's integration facilitated layered combat support, including intrusion detection along contested borders. The S-band frequency (2492.028 MHz) in NavIC offers inherent advantages over L-band , including reduced susceptibility to jamming and spoofing in electronic warfare environments, supporting operations amid Indo-Pacific tensions where adversaries might disrupt U.S.-controlled systems. This enhances , minimizing vulnerability to signal denial, though full anti-jam performance depends on receiver hardware. NavIC integrates with inertial navigation systems (INS) in platforms like BrahMos supersonic cruise missiles for terminal guidance, augmenting indigenous precision in hybrid setups. However, persistent satellite outages— with only four of eleven constellations fully operational on dual bands as of July 2025—necessitate fallback to GPS/GLONASS, underscoring hybrid dependencies despite sovereignty gains.

Economic and Technological Independence Efforts

The pursuit of technological through NavIC has emphasized of critical hardware, including receiver chips and atomic clocks, to counter dependence on imported components prevalent in global GNSS systems. In September 2023, the development of a 'Made in ' chipset for NavIC was announced, incorporating an indigenous based on the Universal Multifunctional Accelerator (UMA) IP core, enabling domestic processing of navigation signals. Complementing this, in July 2024, the (DRDO) partnered with a Bengaluru-based firm to create an indigenous receiver chip capable of acquiring and disseminating from NavIC signals, addressing prior reliance on U.S.-sourced equivalents. Atomic clock indigenization forms a cornerstone of these efforts, aligning with the "" initiative to localize high-precision timing essential for satellite autonomy. successfully developed and tested a domestically produced Rubidium atomic clock, debuting it aboard the satellite launched on May 29, 2023, after nearly a decade of research at the . Ongoing trials since 2023 have focused on space-qualified variants to replace imported units, with prioritizing full domestic production to mitigate vulnerabilities exposed by past clock sourcing delays. These advancements have fostered a nascent GNSS , involving public-private collaborations that build on NavIC's foundational R&D investments, initially budgeted at approximately ₹1,420 (about $210 million) in 2006. While these initiatives have catalyzed domestic industry growth through technology transfers and spin-offs, their economic returns face scrutiny amid operational setbacks relative to mature systems like GPS. NavIC's ecosystem has generated contracts for chip and clock development, enhancing export potential in regional navigation receivers for , yet is hampered by recurrent failures, including malfunctions on multiple satellites as of August 2025, which have rendered over half the constellation partially defunct. In contrast to GPS's decades-long refinement yielding higher reliability, NavIC's accelerated timeline—spanning launches from 2013—has yielded causal lessons in failure modes but underscores challenges in achieving comparable maturity without sustained, failure-tolerant funding. This has prompted debates on cost-effectiveness, as gains in are offset by elevated maintenance needs and delayed commercialization.

Future Enhancements

NVS Series Replacements

The NVS (Navigation with Indian Constellation Second-generation) series represents the upgraded successor to the original IRNSS satellites, designed to address reliability issues such as failures and payload in the first-generation constellation. These satellites incorporate an indigenous Atomic Standard (IRAFS) for improved timing accuracy, support for L1-band signals alongside existing L5 and S bands, and compatibility with GPS L1 signals to enhance and service coverage. Each NVS is engineered for a minimum operational life of 12 years, providing greater than many predecessors, and features enhanced in payloads to mitigate single-point failures observed in earlier IRNSS units. NVS-01, the inaugural satellite in the series, was launched on May 29, 2023, aboard GSLV-F12 from , achieving geosynchronous transfer (GTO) with a of 2,232 kg. It marked the first deployment of India's domestically developed IRAFS, which has demonstrated stable performance in , outperforming imported clocks used in prior IRNSS satellites by reducing frequency drift and improving positioning precision. Positioned to replace the aging IRNSS-1G, augments the NavIC constellation's core services while introducing L1 capabilities for broader civilian and interoperable applications. Follow-on satellite NVS-02 launched on January 29, 2025, via GSLV-F15, ISRO's 100th mission, but encountered a critical anomaly shortly after injection into GTO—a malfunction prevented orbit-raising maneuvers, stranding it in an unusable transfer and underscoring ongoing risks in satellite insertion despite successful liftoff. Intended as a replacement for IRNSS-1E at 111.75°E longitude, NVS-02 shared the series' advanced features but highlighted persistent challenges in post-launch operations. To restore full constellation viability amid multiple defunct first-generation satellites, plans launches of NVS-03, NVS-04, and NVS-05 by 2026 using GSLV vehicles, with NVS-03 targeted for late 2025 or early 2026, followed by the others at six-month intervals. These deployments aim to achieve seven operational satellites for robust regional coverage, but progress has been delayed by qualification testing of the indigenous atomic clocks to ensure in-orbit reliability. The series collectively seeks to phase out problematic IRNSS units, bolstering redundancy without expanding beyond regional scope.

Expansion to Global Coverage

India's Navigation with Indian Constellation (NavIC) system is envisioned to evolve into a global network through the NavIC 2.0 initiative, targeting a constellation of 26 satellites by 2035 to achieve worldwide coverage comparable to established global satellite systems (GNSS) like GPS. This expansion aims to provide positioning accuracy rivaling international standards, enabling seamless integration for applications beyond the current regional footprint extending 1,500 km from Indian borders. In the interim, a phased approach includes augmenting the existing seven operational satellites to 11, enhancing regional redundancy and signal availability while laying groundwork for broader interoperability. International collaborations are being pursued to bolster equatorial coverage and promote NavIC signal adoption in compatible devices, potentially through partnerships with foreign space agencies and GNSS providers for shared augmentation data. However, realizing this global ambition faces substantial hurdles, including fiscal pressures from escalating development costs and historical underfunding of indigenous space innovations, which have delayed prior milestones. Technical feasibility remains unproven at scale, particularly for maintaining precision and orbital stability across an expanded fleet, compounded by the absence of demonstrated (LEO) navigation elements critical for sub-meter accuracy enhancements. These constraints underscore the need for rigorous validation of roadmap timelines against empirical performance data from ongoing tests.

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  95. https://www.hindustantimes.com/cities/mumbai-news/navics-hurdles-project-govt-s-reluctance-to-fund-innovation-101738954406927.html
  96. https://www.researchgate.net/publication/380080418_Challenges_and_Future_Applications_for_IRNSS_with_Machine_Learning_Algorithms
  97. https://www.fintechshield.co.in/post/navic-gps-everything-you-need-to-know-about-india-s-navigation-system
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