The 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), is an autonomous regional satellite navigation system that provides accurate real-time positioning and timing services.

It covers India and a region extending 1,500 km (930 mi) around it, with plans for further extension. 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.

The system currently consists of a constellation of eight satellites, with two additional satellites on ground as stand-by.

The constellation is in orbit as of 2018.

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 and some consumer mobile phones with support for it have been available since the first half of 2020.

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

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.

The Indian government approved the project in May 2006.

As per National Defense Authorization Act (NDAA) 2020, United States Secretary of Defense in consultation with Director of National Intelligence will designate NavIC, Galileo and QZSS as allied navigational satellite system.

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, in Karnataka on 28 May 2013.

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.

The total cost of the project was expected to be ₹14.2 billion (US$178 million), with the cost of the ground segment being ₹3 billion (US$38 million), each satellite costing ₹1.5 billion (US$19 million) and the PSLV-XL version rocket costing around ₹1.3 billion (US$16 million). The planned seven rockets would have involved an outlay of around ₹9.1 billion (US$114 million).

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$281 million).

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

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

In 2020, Qualcomm launched four Snapdragon 4G chipsets and one 5G chipset with support for NavIC.

NavIC is planned to be available for civilian use in mobile devices, after Qualcomm and ISRO signed an agreement.

To increase compatibility with existing hardware, ISRO will add L1 band support. For strategic application, Long Code support is also coming.

Time-frame - 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, and India also launched 3 new satellites to supplement this.

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. IRNSS-1B was launched on 4 April 2014 on-board PSLV-C24 rocket. The satellite has been placed in geosynchronous orbit. IRNSS-1C was launched on 16 October 2014,[ IRNSS-1D on 28 March 2015, IRNSS-1E on 20 January 2016, IRNSS-1F on 10 March 2016 and IRNSS-1G was launched on 28 April 2016.

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.

IRNSS-1I was launched on 12 April 2018 to replace it.

System description - The IRNSS system comprises a space segment and a support ground segment.

Space segment - The constellation consists of 8 satellites. Three of the eight 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 five satellites are in inclined geosynchronous orbit (GSO). Two of them cross the equator at 55° E and two at 111.75° E.

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

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)

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.

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.

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.

16 IRIMS are currently operational and are supporting IRNSS operations

few more are planned in Brunei, Indonesia, Australia, Russia, France and Japan.

CDMA ranging is being carried out by the four IRCDR stations on 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.

ISRO is also under discussion with CNES for a NavIC ground reference station in France.

ISRO is planning a NavIC ground station at Cocos (Keeling) Islands and is in talks with the Australian Space Agency.

Signal - NavIC signals will consist of a Standard Positioning Service and a Precision Service.

The navigation signals themselves would be transmitted in the S-band frequency (2–4 GHz) 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.

Accuracy - The system is intended to provide an absolute position accuracy of better than 10 metres (33 ft) throughout the Indian landmass and better than 20 metres (66 ft) in the Indian Ocean as well as a region extending approximately 1,500 km (930 mi) around India.

The Space Applications Centre in 2017 said NavIC will provide standard positioning service to all users with a position accuracy up to 5 m.[58] The GPS, for comparison, has a position accuracy of 20–30 m.

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.

The US banks 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 India's case, 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 is more accurate than GPS.

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.

These additional four satellites will be made during 12th FYP and will be launched in the beginning of 13th FYP in geosynchronous orbit of 42° inclination.

Also, the development of space-qualified Indian made atomic clocks was initiated, along with a study and development initiative for an all optical atomic clock (ultra stable for IRNSS and deep space communication).

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).

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 will launch on GSLV-Mk2 in 2022.

Study and analysis for Global Indian Navigation System (GINS) was initiated as part of the technology and policy initiatives in the 12th FYP (2012–17).

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.

As per new 2021 draft policy, 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 remain interoperable and free for global public use.

ISRO has proposed to Government of India to expand the constellation for global coverage by initially placing twelve satellites in Medium Earth Orbit (MEO)

IRNSS is an independent regional navigation satellite system being developed by India.

It is designed to provide accurate position information service to users in India as well as the region extending up to 1500 km from its boundary, which is its primary service area.

An Extended Service Area lies between primary service area and area enclosed by the rectangle from Latitude 30 deg South to 50 deg North, Longitude 30 deg East to 130 deg East.

IRNSS will provide two types of services, namely, Standard Positioning Service (SPS) which is provided to all the users and Restricted Service (RS), which is an encrypted service provided only to the authorised users. The IRNSS System is expected to provide a position accuracy of better than 20 m in the primary service area.

Terrestrial, Aerial and Marine Navigation

Disaster Management

Vehicle tracking and fleet management

Integration with mobile phones

Precise Timing

Mapping and Geodetic data capture

Terrestrial navigation aid for hikers and travellers

Visual and voice navigation for drivers

The space research activities were initiated in our country during the early 1960’s, when applications using satellites were in experimental stages even in the United States.

With the live transmission of Tokyo Olympic Games across the Pacific by the American Satellite ‘Syncom-3’ demonstrating the power of communication satellites, Dr.Vikram Sarabhai, the founding father of Indian space programme, quickly recognized the benefits of space technologies for India.

Dr. Sarabhai was convinced and envisioned that the resources in space have the potential to address the real problems of man and society. As Director, Physical Research Laboratory (PRL) located in Ahmedabad, Dr. Sarabhai convened an army of able and brilliant scientists, anthropologists, communicators and social scientists from all corners of the country to spearhead the Indian space programme.

To spearhead the space research activities, Indian National Committee for Space Research (INCOSPAR) was set up in 1962 under the Department of Atomic Energy. Subsequently, Indian Space Research Organisation (ISRO) was established in August 1969, in place of INCOSPAR. The Government of India constituted the Space Commission and established Department of Space (DOS) in June 1972 and brought ISRO under DOS in September 1972.

Since inception, the Indian space programme has been orchestrated well and had three distinct elements such as, satellites for communication and remote sensing, the space transportation system and application programmes.

In 1967, the first ‘Experimental Satellite Communication Earth Station (ESCES)’ located in Ahmedabad was operationalized, which also doubled as a training centre for the Indian as well as International scientists and engineers.

To establish that a satellite system can contribute to the national development, ISRO was clear that it need not wait for its own satellites to begin application development, while foreign satellites could be used in the initial stages.

However, before trying out a full-fledged satellite system, some controlled experiment to prove the efficacy of television medium for national development was found necessary. Accordingly, a TV programme on agricultural information to farmers ‘KrishiDarshan’ was started, which received good response.

The next logical step was the Satellite Instructional Television Experiment (SITE), hailed as ‘the largest sociological experiment in the world’ during 1975-76.

This experiment benefited around 200,000 people, covering 2400 villages of six states and transmitted development oriented programmes using the American Technology Satellite (ATS-6).

The credit of training 50,000 science teachers primary schools in one year goes to SITE.

SITE was followed by the Satellite Telecommunication Experiments Project (STEP), a joint project of ISRO-and Post and Telegraphs Department (P&T) using the Franco-German Symphonie satellite during 1977-79.

Conceived as a sequel to SITE which focused on Television, STEP was for telecommunication experiments. STEP was aimed to provide a system test of using geosynchronous satellites for domestic communications, enhance capabilities and experience in the design, manufacture, installation, operation and maintenance of various ground segment facilities and build up requisite indigenous competence for the proposed operational domestic satellite system, INSAT, for the country.

SITE was followed by the ‘Kheda Communications Project (KCP)’, which worked as a field laboratory for need-based and locale specific programme transmission in the Kheda district of Gujarat State. KCP was awarded the UNESCO-IPDC (International Programme for the Development of Communication) award for rural communication efficiency in the 1984.

During this period, the first Indian spacecraft ‘Aryabhata’ was developed and was launched using a Soviet Launcher. Another major landmark was the development of the first launch vehicle SLV-3 with a capability to place 40 kg in Low Earth Orbit (LEO (Low Earth Orbit) ), which had its first successful flight in 1980.

Through the SLV-3 programme, competence was built up for the overall vehicle design, mission design, material, hardware fabrication, solid propulsion technology, control power plants, avionics, vehicle integration checkout and launch operations. Development of mult-istage rocket systems with appropriate control and guidance systems to orbit a satellite was a major landmark in our space programme.

In the experimental phase during 80’s, end-to-end capability demonstration was done in the design, development and in-orbit management of space systems together with the associated ground systems for the users.

Bhaskara-I & II missions were pioneering steps in the remote sensing area whereas ‘Ariane Passenger Payload Experiment (APPLE)’ became the forerunner for future communication satellite system.

Development of the complex Augmented Satellite Launch Vehicle (ASLV), also demonstrated newer technologies like use of strap-on, bulbous heat shield, closed loop guidance and digital autopilot.

This paved the way for learning many nuances of launch vehicle design for complex missions, leading the way for realisation of operational launch vehicles such as PSLV and GSLV.

During the operational phase in 90’s, major space infrastructure was created under two broad classes: one for the communication, broadcasting and meteorology through a multi-purpose Indian National Satellite system (INSAT), and the other for Indian Remote Sensing Satellite (IRS) system.

The development and operationalisation of Polar Satellite Launch Vehicle (PSLV) and development of Geo-synchronous Satellite Launch Vehicle (GSLV) were significant achievements during this phase.