The Indian Regional Navigation Satellite System(IRNSS) with an operational title NavIC(Navigation with Indian Constellation) is a local navigation system that is intended to provide accurate position information to all its users in its primary service area(which includes the Republic of India and the region extending up to 1500Km from its boundary). It has an extended service area that encloses the region between the primary service area and a rectangle bounded by Latitude 30 deg South to latitude 50 deg North, and Longitude 30 deg East to longitude 130 deg East.
WHY NavIC?
Access to foreign government-administered Navigation Satellite systems is not assured in times of distress. In 1999, when the Kargil war was about to begin, one of the first things the Indian government sought was the GPS(Global Positioning System) data of the Kargil Valley. The #GPS is a space-based navigation system maintained by the government of the United States. The US government denied sharing the information with the Indian military. This intensified the need for an indigenous Satellite Navigation System.
The Government of India approved this project in May 2013. According to the National Defense Authorization Act(NDAA) 2020, the United States Secretary of Defense, in deliberation with the Director of National Intelligence will designate #NavIC as Allied Navigational Satellite System.
DEVELOPMENT
This is an autonomous Indian satellite-based positioning system for critical National applications. It was started in May 2013 at the Deep Space Network(DSN) campus of the Indian Space Research Organisation(#ISRO). By April 2018, ISRO developed a total of nine satellites in the IRNSS series, out of which 8 satellites were launched successfully into their orbits.
The expected total cost of the project was ₹14.2 billion($199 million). But, the replacement of two satellites and their PSLV-XL launches in March 2017 increased the total budget to ₹22.46 billion($315 million).
NavIC presently provides two sorts of services. The Standard Positioning Service(SPS) is open to all users and has an accuracy of 20m. The Restricted Service(RS) is encrypted and can be accessed only by authorized users. It can detect the movement of objects within the range of 10m. The use of NavIC-based vehicle tracking systems was declared mandatory for all commercial vehicles in India from 1 April 2019.
American chipmaker Qualcomm announced the addition of NavIC support to their chipsets in October 2019. In January 2020, Qualcomm released three chipsets Snapdragon 460, 720G, 662 which support Navigation with Indian Constellation(NavIC). NavIC is considered to be available for commoners use in mobile phones after an agreement is signed between Qualcomm and Indian Space Research Organisation.
WORKING
NavIC comprises of two segments, the Ground and Space segments. The space segment contains 8 satellites, of which three are positioned in the Geostationary orbit, and the other four satellites are inclined in the Geo-Synchronous orbit.
The ground segment operates and maintains the constellation. It is comprised of :
IRNSS Data Communication Network(IRDCN)
IRNSS CDMA Ranging Stations (IRCDR)
IRNSS Range and Integrity Monitoring Stations (IRIMS)
Laser Ranging Stations
IRNSS Spacecraft Control Facility (IRSCF)
IRNSS Network Timing Centre (IRNWT)
ISRO Navigation Centre (INC)
Navic signal consists of a Precision service and Standard Positioning service. These are carried on S-band (2492.028 MHz) and L5 (1176.45 MHz). The NavIC system has an embedded messaging interface that sends alert messages to a specified geographic area to warn about the disasters in advance.
LIST OF SATELLITES
As discussed earlier, by April 2018, ISRO developed a total of nine satellites in the #IRNSS series, out of which 8 satellites were launched successfully into their orbits. The details of the satellites are:
The satellites of the IRNSS series that are organized for the future are as follows:
In 2017, the three spectra time-supplied atomic clocks in the IRNSS-1A failed and hence resulted in the non-functionality of the satellite. Thus a replacement of the satellite was required. In June 2017, the IRNSS-1H was launched as a replacement for IRNSS-1A. The attempt was unsuccessful due to the failure of the PSLV-C39 machine. On 12 April 2018, the second standby satellite IRNSS-1I was successfully placed into orbit.
APPLICATIONS
A few more applications of NavIC are as follows:
Terrestrial navigation aid for hikers and travelers.
Tracking vehicles and fleet management for businesses.
Aerial and marine navigation.
Improved Timing.
Disaster Management.
Improved Mapping and Geodetic data capture.
Visual and voice navigation for drivers.
GPS OR NavIC?
The Navigation with Indian Constellation has an accuracy of about 10m in the landmass of India and about 20m of accuracy in the area of 1500km surrounding its border. GPS has an accuracy of 20-30m, which states that NavIC is more accurate. GPS is dependent only on the L band but NavIC has a dual-frequency(L and S bands). GPS is dependent on the atmospheric model to determine its frequency error. Therefore, it must be updated regularly to obtain the true error. But, in the case of NavIC, the actual error is dependent on the delay of the dual frequencies and hence is not dependent on any system in calculating the actual frequency error. This justifies that NavIC is more accurate than GPS.
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