Explained: Hawk eye in the sky

Indian Space Research Organisation’s Polar Satellite Launch Vehicle (PSLV-C27) carrying India’s fourth navigation satellite IRNSS-1D, lifts off from Satish Dhawan Space Center in Sriharikota on Saturday. (Source: PTI)

The IRNSS-1D, launched on Saturday, is the fourth satellite in a constellation of a planned seven-satellite Indian navigational system. The IRNSS, set to be fully operational by the middle of next year, will have applications for disaster management and vehicle tracking, and, most importantly, for the Indian armed forces. SUSHANT SINGH explains.

What is the Indian Regional Navigation Satellite System (IRNSS)?

It is a GPS-like regional satellite-based navigation system being developed by India. Unlike the Global Positioning System (GPS) operated by the United States, the Russian GLONASS, the European Union’s Galileo or China’s Beidou Navigation Satellite System (BDS) which have a global coverage, IRNSS will focus on the region extending up to 1,500 km from India’s boundaries, between longitude 40° E and 140° E, and latitude ± 40°. The project will cost around Rs 1,420 crore.

How many satellites will be part of the IRNSS?

IRNSS is planned as a constellation of seven satellites. Three of them will be placed in a geostationary orbit, located at 34° E, 83° E and 131.5° E, while the other four will be in geosynchronous orbit at an inclination angle of 29°, placed two each with the equator crossing at 55° and 111° E. The three geostationary satellites will appear fixed in the sky while the four geosynchronous satellites will appear to move in the figure of ‘8′ when observed from the ground.

IRNSS 1D, which was launched on Saturday from Sriharikota, is the fourth satellite to be launched. There are plans to initiate work to augment the IRNSS system with four additional satellites after the system becomes operational. That will bring the IRNSS to 11 satellites. That is still small in comparison to the Chinese Beidou Navigation Satellite System, which is planned to consist of 35 satellites.

What will be the ground infrastructure of IRNSS?

The ground infrastructure for IRNSS comprises stations for generation and transmission of navigation parameters, satellite control, satellite ranging and monitoring. A total of 20 such stations are planned, most of them located at airports along with Indian GPS Aided Geo Augmented Navigation (GAGAN) ground elements. In addition, IRNSS will have two Master Control Stations, which are likely to be co-located with GAGAN Indian Master Control Centres.

When will the IRNSS become operational?

Basic navigational services in limited areas can be provided with four satellites in orbit now. But the system at this stage will be used by ISRO to test its accuracy to validate the IRNSS. All the seven satellites are scheduled to in orbit by early next year, and the IRNSS is planned to be fully operational by mid-2016.

What will be the accuracy of IRNSS coverage?

The IRNSS shall provide positional accuracies similar to the GPS – 10 m over the Indian landmass, and 20 m over the Indian Ocean. As is the case with the GPS and the US military, IRNSS will provide a more accurate restricted service for the Indian armed forces and other special authorized users.

What are the applications of IRNSS?

Besides providing terrestrial, aerial and marine navigation, IRNSS will help in disaster management, vehicle tracking and fleet management, integration with mobile phones, precise timing, mapping and geodetic data capture, terrestrial navigation aid for hikers and travelers and in visual and voice navigation for drivers.

However, the most important usage of the IRNSS will be for the Indian armed forces, which can confidently rely on assured positional data during hostilities. Most modern weapon systems like guided missiles and bombs use navigation systems for targeting. An indigenous system like the IRNSS allows the development and execution of such capabilities in a reliable manner.

Why is IRNSS so critical to the military?

IRNSS is a strategic requirement for modern war-fighting. Because access to foreign government-controlled navigation satellite systems such as the American GPS or EU’s Galileo is not guaranteed during hostilities — as experienced by India banking on the GPS during the Kargil War — it is critical to have India’s own system in the likely area of military operations. A system run by another country may be switched off at any time leading to complete

Source:: Indian Express