Indian Regional Navigation Satellite System

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Navigation with Indian Constellation (NavIC)
Indian Regional Navigation Satellite System (IRNSS)
Country/ies of originIndia
Operator(s)ISRO
TypeMilitary, Commercial
StatusOperational
CoverageRegional (up to 1,600 km from borders)
Accuracy1 m or 3 ft 3 in (public)
10 cm or 3.9 in (encrypted)
Constellation size
Total satellites8
Satellites in orbit7 (IRNSS 1I launched completing the series)
First launch1 July 2013
Last launch12 April 2018
Total launches9
Orbital characteristics
Regime(s)Geosynchronous orbit
Orbital height35,786 kilometres (22,236 miles)
Other details
Cost₹22.46 billion (US$315 million), to March 2017[1]
Geodesy
Azimutalprojektion-schief kl-cropped.png
Fundamentals
Concepts
Technologies
Standards (history)
  • v
  • t

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),[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. 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.[4] The system currently consists of a constellation of seven satellites,[5][6] with two additional satellites on ground as stand-by.[7]

The constellation is in orbit as of 2018, and the system was expected to be operational from early 2018[8][9] after a system check.[10] 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[11][12] and it is planned to become available in consumer mobile phones in the first half of 2020.[13]

There are plans to expand the NavIC system by increasing its constellation size from 7 to 11.[14]

Background[]

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 United States denied the Indian request for Global Positioning System (GPS) data for the Kargil region which would have provided vital information.[15] The Indian government approved the project in May 2013.

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.[16]

Development[]

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.[17] 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 a 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.[18]

The total cost of the project was expected to be ₹14.2 billion (US$199 million), with the cost of the ground segment being ₹3 billion (US$42 million), each satellite costing ₹1.5 billion (US$21 million) and the PSLV-XL version rocket costing around ₹1.3 billion (US$18 million). The planned seven rockets would have involved an outlay of around ₹9.1 billion (US$128 million).[7][19][20]

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, to March 2017, at ₹22.46 billion (US$315 million)[1]

The NavIC signal was released for evaluation in September 2014.[21]

From 1 April 2019, use of AIS-140 compliant NavIC-based vehicle tracking systems were made compulsory for all commercial vehicles in India.[11][12]

On 20 January 2020, Qualcomm launched three new 4G chipsets, Snapdragon 460, Snapdragon 662 and Snapdragon 720G with support for Navigation with Indian Constellation (NavIC).[22][23]On 31 August 2020, Qualcomm launched new 4G chipset, Snapdragon 732G with support for Navigation with Indian Constellation (NavIC). On 22 September 2020, Qualcomm launched new 5G chipset, Snapdragon 750G with support for Navigation with Indian Constellation (NavIC). NavIC is planned to be available for civilian use in mobile devices, after Qualcomm and Indian Space Research Organisation signed an agreement.[13][24]

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,[25] and India also launched 3 new satellites to supplement this.[26]

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.[27][28] IRNSS-1B was launched on 4 April 2014 on-board PSLV-C24 rocket. The satellite has been placed in geosynchronous orbit.[29] IRNSS-1C was launched on 16 October 2014,[30] IRNSS-1D on 28 March 2015,[31] IRNSS-1E on 20 January 2016,[32] IRNSS-1F on 10 March 2016 and IRNSS-1G was launched on 28 April 2016.[33]

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 4th stage of the rocket.[34] IRNSS-1I was launched on 11 April 2018 to replace it.[35][36]

System description[]

Coverage of NavIC

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 32.5° E, 83° E, and 131.5° E longitude, approximately 36,000 km (22,000 mi) above earth surface. Remaining five satellites are in inclined geosynchronous orbit (GSO). Two of them cross equator at 55° E and two at 111.75° E.[37][38] The four GSO satellites will appear to be moving in the form of an "8".[39]

Ground segment[]

Ground Segment is responsible for the maintenance and operation of the IRNSS constellation. The Ground segment comprises:[37]

  • 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.[40] 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.[37][41]

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.[42]

14 IRIMS are currently operational and are supporting IRNSS operations. 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) w.r.t 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 viz. satellite ephemeris, clock corrections, integrity parameters and secondary parameters viz. iono-delay corrections, time offsets w.r.t UTC and other GNSS, 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.[43] ISRO is also under discussion with CNES for a NavIC ground reference station in France.[44] ISRO is planning a NavIC ground station at Cocos (Keeling) Islands and is in talks with Australian Space Agency.[45]

Signal[]

NavIC signals will consist of a Standard Positioning Service and a Precision Service. Both will be carried on L5 (1176.45 MHz) and S band (2492.028 MHz).[46] The SPS signal will be modulated by a 1 MHz BPSK signal. The Precision Service will use BOC(5,2). 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.[47]

Accuracy[]

The system is intended to provide an absolute position accuracy of better than 10 metres (33 ft) throughout 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.[48] The Space Applications Centre in 2017 said NavIC will provide standard positioning service to all users with a position accuracy up to 5 m.[47] The GPS, for comparison, had a position accuracy of 20–30 m.[49] Unlike GPS which is dependent only on L-band, NavIC has dual frequency (S and L bands). When low frequency signal travels through atmosphere, its velocity changes due to atmospheric disturbances. US banks on 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 dual frequency (S and L bands). Therefore, NavIC is not dependent on any model to find the frequency error and is more accurate than GPS.[50]

List of satellites[]

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

IRNSS series satellites[]

IRNSS-1 series satellites[37][51]
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.[42][52][53]
IRNSS-1B I002 I02 2014-017A 39635 4 April 2014 PSLV-XL-C24 Geosynchronous (IGSO) / 55°E, 29° inclined orbit Operational
IRNSS-1C I003 I03 2014-061A 40269 16 October 2014 PSLV-XL-C26 Geostationary (GEO) / 83°E, 5° inclined orbit Operational
IRNSS-1D I004 I04 2015-018A 40547 28 March 2015 PSLV-XL-C27 Geosynchronous (IGSO) / 111.75°E, 31° inclined orbit Operational
IRNSS-1E I005 I05 2016-003A 41241 20 January 2016 PSLV-XL-C31 Geosynchronous (IGSO) / 111.75°E, 29° inclined orbit Operational
IRNSS-1F I006 I06 2016-015A 41384 10 March 2016 PSLV-XL-C32 Geostationary (GEO) / 32.5°E, 5° inclined orbit Operational
IRNSS-1G I007 I07 2016-027A 41469 28 April 2016 PSLV-XL-C33 Geostationary (GEO) / 129.5°E, 5.1° inclined orbit Operational The satellite is being used for NavIC's short message broadcast service.[40]
IRNSS-1H 31 August 2017 PSLV-XL-C39 Launch Failed The payload fairing failed to separate and satellite could not reach the desired orbit.[34][54] It was meant to replace defunct IRNSS-1A.[52][14]
IRNSS-1I I009 2018-035A 43286 12 April 2018 PSLV-XL-C41 Geosynchronous (IGSO) / 55°E, 29° inclined orbit Operational [55]
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[]

NVS series satellites[37][51]
Satellite SVN PRN Int. Sat. ID NORAD ID Launch Date Launch Vehicle Orbit Status Remarks
NVS-01 November 2021 GSLV-MK2 F-14 Geostationary (GEO) / 129.5°E, 5.1° inclined orbit Planned Planned replacement of IRNSS-1G. Features extended lifespan and new civilian payload for low power devices.[40][56]
NVS-02 Geosynchronous (IGSO), 42° inclined orbit Planned [40]
NVS-03 Geosynchronous (IGSO), 42° inclined orbit Planned [40]
NVS-04 Geosynchronous (IGSO), 42° inclined orbit Planned [40]
NVS-05 Geosynchronous (IGSO), 42° inclined orbit Planned [40]

Clock failure[]

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.[57][58] 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.[59] ISRO reported it had replaced the atomic clocks in the two standby satellites, IRNSS-1H and IRNSS-1I., in June 2017[14] The subsequent launch of IRNSS-1H, as a replacement for IRNSS-1A, was unsuccessful when PSLV-C39 mission failed on 31 August 2017.[14][60] The second standby satellite, IRNSS-1I, was successfully placed into orbit on 12 April 2018.[55]

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,[14] in May 2018 a failure of a further 4 clocks was reported, taking the count to 9 of the 24 in orbit.[61]

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.[14]

Future developments[]

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.[62] 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.[63][64] Also, the development of space-qualified Indian made atomic clocks was initiated,[65] along with a study and development initiative for an all optical atomic clock (ultra stable for IRNSS and deep space communication).[66][62]

ISRO will be launching 5 next generation satellite featuring new payloads and extended lifespan of 12 years. ISRO will launch 5 new satellite viz. NVS-01, NVS-02, NVS-03, NVS-04 and NVS-05. These will supplement and augment the current constellation of satellites. The new satellite will feature the L5 and S band and introduces a new interoperable civil signal in L1 band in the navigation payload. This introduction of new L1 band will help cater to NavIC proliferation in wearable smart and IoT devices featuring low power navigation system. NVS-01 is a replacement for IRNSS-1G satellite and will launch on GSLV-Mk2 in 2021-22[67][40]

Global Indian Navigation System (GINS)[]

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).[66] 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.[68] As per new 2021 draft policy,[69] 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.[70]

See also[]

  • BeiDou Navigation Satellite System
  • Galileo (satellite navigation)
  • Global Positioning System
  • GLONASS
  • GPS Aided GEO Augmented Navigation
  • Satellite navigation
  • Quasi-Zenith Satellite System

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Footnotes[]

  1. ^ SATNAV Industry Meet 2006. ISRO Space India Newsletter. April – September 2006 Issue.

External links[]

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