Indian Regional Navigational Satellite System ( IRNSS)
The Indian Regional Navigational Satellite System (IRNSS) is an autonomous regional satellite navigation system being developed by Indian Space Research Organisation which would be under total control of Indian government.
The government approved the project in May 2006, with the intention of the system to be completed and implemented by 2014. The first satellite of the proposed constellation, developed at a cost of Rs.1,600 crore (16 billion rupees), is expected to be launched in last quarter of 2011.
A goal of complete Indian control has been stated, with the space segment, ground segment and user receivers all being built in India. It is unclear if recent agreements with the Russian government to restore their GLONASS system will supersede the IRNSS project or feed additional technical support to enable its completion. However reports came in Apr 2010 that India plans to starts launching satellites by end of 2011 and six months periodic launches take place. It means the IRNSS optimally functional by 2014
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 20 meters throughout India and within a region extending approximately 2,000 km around it.
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.
The proposed IRNSS will be designed indigenously and launched from Indian soil through Polar Satellite Launch Vehicle (PSLV). The proposed satellite specifications are given below. • Dry mass of the satellite ~ 600 kgs • Power generation 1400 watts • Fuel loading capacity ~ 785 kgs • Accommodates navigation payload of weight 102 kgs and 375 watts of power
It will provide signal generation on board and there will be two downlinks providing dual frequency operation with EIRP of 31.5 dBW at EOC. INRSS payload will have 3 Rubidium clocks and Navigation data up link will be through telemetry command link. The payload beam of GSOS will be steered to take care of the inclination.
IRNSS Ground Segment Functionality The ground segment consists of MCC, INRSS Ranging and Integrity Monitoring (IRIM) Stations and IRNSS telemetry and command stations. The function of MCC is to estimate and predicts the ephemeris; calculate corrections for SV clock & maintain IRNSS time, Ionospheric corrections and Integrity. The function of IRNSS IRIM stations will be receiving the data from the GEOs and GSOs, transmit the data to MCC and one way ranging of the GEOs & GSOs in S band. The function of IRNSS telemetry and command stations will be to receive telemetry from the IRNSS constellation, Telecomm and the IRNSS constellation and navigation updates. USER Segment
The user segment will consist of a specially designed inter operable dual frequency receiver, which may receive the data from other constellation of navigation satellite. User segment receiver may be called as multi constellation receiver. The user receiver to get the required position accuracy will continuously track all the seven satellites of INRSS. The user receiver will have minimum G/T of -25 dB/K similar to GPS.
The INRSS is under planning stage and ISRO is the main agency to design and implement the entire infrastructure required for operation of the system. It has also to do certification and validation of the signal will be before declaring operational for the users. https://www.facebook.com/photo.php?f...&type=1&ref=nf