ANSWER: 1 and 2
Explanation:
With the launch of the IRNSS-1E satellite On Wednesday morning, India moved a step closer to completing its network of satellites that will form a space-based regional navigation system providing location services over India and neighboring areas. In other words, our very own kind of GPS. Once the system is complete and comes into use, it will provide an alternative to the US-developed GPS, or global positioning system that is so commonly used in a variety of applications. The IRNSS is ‘regional’ and will cover the area over India and 1,500 km from India’s political boundaries, unlike the GPS which is ‘global’. However, because it is specific to the Indian region, it is expected to be even more accurate than the GPS. The GPS system uses 24 satellites at present though it can support a constellation of 30 satellites. The actual number of satellites in use at a given time varies. The IRNSS constellation had already started working after the launch of the fourth satellite in March last year, the minimum number required to make the system operational. ISRO and some educational institutions already receive the data and use it for developing some location solutions. The fifth and the subsequent two satellites will make the system stronger and more reliable. The development of IRNSS has happened alongside that of GAGAN (GPS-Aided Geo Augmentation Navigation) which is meant for navigation services for civil aircraft over the Indian region. GAGAN, which was authorised for use by the Directorate General of Civil Aviation in April 2015, can also provide services to other sectors like highways, railways, maritime transport, survey, telecom, etc.
