IRNSS, GAGAN, GSAT, ASTROSAT
Indian Regional Navigation Satellite System (IRNSS)
- With an investment of 1420 Cr, 7 Satellites to be put in space by ISRO
- Will cover India + 1,500 km beyond its borders
- 3 satellites will be put in geostationary orbit + 4 satellites in pairs in two inclined geosynchronous orbits
- From the ground, these satellites will appear to travel in figures of ‘8’ during the course of a day
- Will be at a height of about 36,000 km, launched from Satish Dawan Space Centre in Sriharikota
- Will need a special receiver equipment to use navigation data, standard GPS receiver will not work
At present only two countries have fully functional global navigation systems
|USA||GPS – Global|
|Russia||GLONASS – Global|
|China||Beidou – Regional → Will be global by 2020|
|Japan||Quasi-Zenith Satellite System|
|European Union||Galileo (GNSS)|
IRNSS Scientific principle
- Use two microwave frequency bands: L5 and S which travel at speed of light.
- Receiver will calculate the delay between microwave’s transmission & its reception, thus we get coordinates on earth.
- For above microwave-calculation, Satellites have to periodically transmit their precise position in orbit with exact time, hence, they need to carry extremely accurate clocks with long shelf-life.
- Therefore, Each IRNSS satellite is equipped with rubidium atomic clocks, to keep precise time.
- Will provide two kinds of services viz. Standard Positioning Services, available to all users, and an encrypted service, provided only to authorized users
- IRNSS System is expected to provide a position accuracy of better than 20 m in the primary service area
- To be able to use the IRNSS satellites, ISRO have to launch at least four of the seven planned IRNSS satellites
Global Positioning System Aided Geo Augmented Navigation System (GAGAN)
- A joint effort by the ISRO & Airports Authority Of India (AAI) for civil aviation purposes
- Aimed to help Air traffic control and helps pilots fly / land aircrafts in bad weather
- Depends on GPS (American navigation system)
India has become 4th nation after US, Europe & Japan to have inter-operable Satellite Based Augmentation System (SBAS) & 1st in the world to serve the equatorial region
Working Pattern – GAGAN
- Works with the help of 3 Geostationary Satellites viz. GSAT-8, GSAT-10 and GSAT-15
- works by augmenting and relaying data from GPS satellites with the help of augmentation satellites and earth-based reference stations
- GAGAN system corrects any anomalies in the position data and gives accurate routes, landing guidance and time saving information to the pilots
- system would be available for the member states of the South Asian Association for Regional Cooperation (SAARC)
- It will be able to help pilots to navigate in the Indian airspace by an accuracy of 3 m
Major Benefits of GAGAN
- Improved efficiency,
- Direct routes
- Increased fuel savings
- Significant cost savings
Major drawback → only those aircraft that are fitted with satellite-based wide area augmentation system (SBAS) will be able to use the new technology
- INSAT-3E is a communication satellite that powers DD & private TV channels, internet & radio signals.
- INSAT-3E is getting old and outdated, even stopped working in March 2014, after serving for almost a decade, hence need to be replaced with GSAT-16
- GSAT 16 is configured to carry a total of 48 communication transponders, the largest number of transponders carried by a communication satellite developed by ISRO so far
- The designed on-orbit operational life of GSAT-16 is 12 years.
- Placed in Geosynchronous Transfer Orbit at 55 degrees East longitude by European Ariane-5 launcher
- It is aimed at primarily benefiting the country’s strategic and social applications
- Has life period of nine years & will povide S-band communication services in the country
- It includes a first-of-its-kind S-Band antenna with a diameter of six meter. This is the largest antenna ISRO has ever made for a satellite.
- It will offer a Satellite Digital Multimedia Broadcasting (S-band) service, via mobile phones and mobile video/audio receivers for vehicles.
- India’s 1st dedicated astronomy multi-wavelength satellite, aimed at studying distant celestial objects
- ASTROSAT will observe universe in the optical, Ultraviolet, low and high energy X-ray regions of the electromagnetic spectrum
- 1st mission to be operated as a space observatory by ISRO
Scientific objectives of ASTROSAT
- To understand high energy processes in binary star systems containing neutron stars and black holes
- Estimate magnetic fields of neutron stars
- Study star birth regions and high energy processes in star systems lying beyond our galaxy
- Detect new briefly bright X-ray sources in the sky
- Perform a limited deep field survey of the Universe in the Ultraviolet region