Development
As part of the project, ISRO opened a new satellite navigation center within the campus of ISRO
Deep Space Network (DSN) at Byalalu near Bangalore in Karnataka on 28 May 2013.
[2] A network of 21 ranging stations located across the country will provide data for the orbit 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.
[3]
The total cost of the project is expected to be
1420
crore (US$217 million)), with the cost of the ground segment being
300 crore (US$46 million) and each satellites costing
125 crore (US$19 million).
[4][5]
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 the IRNSS functional by 2015.
[6] India also launched 3 new satellites into space to supplement this.
[7]
IRNSS-1A, the first of the seven satellites of the IRNSS constellation, was built at ISRO Satellite Centre, Bangalore, costing
125
crore (US$19 million).
[4][5][8][9] 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).
[10] 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.
[11][12] The satellite was launched on-board
PSLV-C22 on 1 July 2013 from the
Satish Dhawan Space Centre at Sriharikota, while the full constellation is planned to be placed in orbit by 2015.
[9][13][14]
Description
The proposed system would consist of a constellation of seven satellites and a support ground segment. Three of the satellites in the constellation will be located in
geostationary orbit at 32.5° East, 83° East, and 131.5° East
longitude. Two of the
GSOs will cross the equator at 55° East and two at 111.75° East.
[15][
dead link] Such an arrangement would mean all seven satellites would have continuous radio visibility with Indian control stations. The satellite payloads would consist of atomic clocks and electronic equipment to generate the navigation signals.
IRNSS signals will consist of a Special Positioning Service and a Precision Service. Both will be carried on L5 (1176.45 MHz) and S band (2492.08 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.
[16]
The ground segment of IRNSS constellation would consist of a Master Control Center (MCC), ground stations to track and estimate the satellites'
orbits and ensure the integrity of the network (IRIM), and additional ground stations to monitor the health of the satellites with the capability of issuing radio commands to the satellites (TT&C stations). The MCC would estimate and predict the position of all IRNSS satellites, calculate integrity, makes necessary ionospheric and clock corrections and run the navigation software. In pursuit of a highly independent system, an Indian standard time infrastructure would also be established.