Country of origin India Type Military, Commercial | Operator(s) ISRO Status Operational | |
 | ||
Coverage Regional (up to 1,500 km from borders) Precision 10 m (public)
0.1 m (encrypted) | ||
The Indian Regional Navigation Satellite System (IRNSS) with an operational name of NAVIC ("sailor" or "navigator" in Sanskrit, Hindi and many other Indian languages, which also stands for NAVigation with Indian Constellation) is an autonomous regional satellite navigation system that is being set up by India, that will be used to provide accurate real-time positioning and timing services over India and the region extending to 1,500 kilometres (930 mi) around India. The NAVIC system will consist of a constellation of 3 satellites in Geostationary orbit (GEO), 4 satellites in Geosynchronous orbit (GSO), approximately 36,000 kilometres (22,000 mi) altitude above earth surface, and two satellites on the ground as stand-by, in addition to ground stations. The system was developed 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 it was dependent on the American Global Positioning System (GPS) during the Kargil War. The Indian government approved the project in May 2006.
Contents
- Development
- Time Frame
- Description
- IRNSS 1A
- IRNSS 1B
- IRNSS 1C
- IRNSS 1D
- IRNSS 1E
- IRNSS 1F
- IRNSS 1G
- Clock Failure
- References
The constellation of seven NAVIC satellites is already in orbit and the system is expected to be operational from September 2016, after a system check. NAVIC will provide two levels of service, the standard positioning service will be open for civilian use, and a restricted service (an encrypted one) for authorized users (including the military).
Development
As part of the project, the Indian Space Research Organisation (ISRO) opened a new satellite navigation center 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 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.
The total cost of the project is expected to be ₹1,420 crore (US$211 million), with the cost of the ground segment being ₹300 crore (US$45 million). Each satellites costing ₹150 crore (US$22 million) and the PSLV-XL version rocket costs around ₹130 crore (US$19 million) . The seven rockets would involve an outlay of around ₹910 crore (US$135 million). The NAVIC signal was released for evaluation in September 2014.
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 the 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.
Description
The system consists of a constellation of seven satellites and a support ground segment. Three of the satellites in the constellation are located in geostationary orbit (GEO) at 32.5° East, 83° East, and 131.5° East longitude. The other four are inclined geosynchronous orbit (GSO). Two of the GSOs cross the equator at 55° East and two at 111.75° East. The four GSO satellites will appear to be moving in the form of an "8". In addition, various ground-based systems will control, track orbits, check integration and send radio signals to the satellites. The land-based Master Control Center (MCC) will run navigational software.
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). 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 and their solar panels generate 1,400 watts. The system is intended to provide an absolute position accuracy of better than 10 meters throughout Indian landmass and better than 20 meters in the Indian Ocean as well as a region extending approximately 1,500 km around India.
IRNSS-1A
IRNSS-1A was the first out of seven navigational satellite in the Indian Regional Navigation Satellite System (IRNSS) series of satellites to be placed in geosynchronous orbit. It was built at ISRO Satellite Centre, Bangalore, costing ₹125 crore (US$19 million). It has a lift-off mass of 1380 kg, and carries a navigation payload and a C band ranging transponder, which operates in L5 band (1176.45 MHz) and S band (2492.028 MHz). An optimised I-1K bus structure with a power handling capability of around 1600 watts is used and is designed for a ten-year mission. The satellite was launched on-board PSLV-C22 on 1 July 2013 from the Satish Dhawan Space Centre at Sriharikota.
IRNSS-1B
Satellite IRNSS-1B was located in geosynchronous orbit on 4 April 2014 aboard the PSLV-C24 rocket from Satish Dhawan Space Centre, Sriharikota. The satellite will provide navigation, tracking and mapping services.
The IRNSS-1B satellite weighs 1,432 kg and has two payloads: a navigation payload and CDMA ranging payload in addition with a laser retro-reflector. The payload generates navigation signals at L5 and S-band. The design of the payload makes the IRNSS system interoperable and compatible with GPS and Galileo. The satellite is powered by two solar arrays, which generate power up to 1,660 watts, and has a life-time of ten years.
IRNSS-1C
Satellite IRNSS-1C was placed in geostationary orbit on 16 October 2014 aboard PSLV-C26 from the Satish Dhawan Space Centre, Sriharikota.
The IRNSS-1C satellite has two payloads: a navigation payload and CDMA ranging payload in addition with a laser retro-reflector. The payload generates navigation signals at L5 and S-band. The design of the payload makes the IRNSS system interoperable and compatible with GPS and Galileo. The satellite is powered by two solar arrays, which generate power up to 1,660 watts, and has a life-time of ten years.
IRNSS-1D
IRNSS-1D is the fourth IRNSS satellite. It was launched using India's PSLV-C27 on 28 March 2015.
IRNSS-1E
IRNSS-1E is the fifth IRNSS satellite. It was launched on 20 January 2016 using India's PSLV-C31.
IRNSS-1F
IRNSS-1F is the sixth IRNSS satellite. It was launched on 10 March 2016 using India's PSLV-C32.
IRNSS-1G
IRNSS-1G is the seventh IRNSS satellite. It was launched on 28 April 2016 using India's PSLV-C33, which concludes the setting up of the Indian Regional Navigation Satellite System.
Clock Failure
In 2017 it was announced that three rubidium atomic clocks on board IRNSS-1A have all failed. The first failure occurred in July 2016, following which two other clocks also failed. This renders the satellite somewhat redundant and requires replacement. Although the satellite still performs other functions, the data will be coarse, and thus cannot be used for accurate measurement. ISRO plans to replace it with IRNSS 1H in the second half of 2017.