INSAT-4E, also known as GSAT-6, is a multimedia communication satellite that will offer a Satellite Digital Multimedia Broadcasting (S-DMB) service across several digital multimedia terminals or consoles which can be used to provide information services to vehicles on the fly and to the mobile phones. The satellite will be used for other social and strategic applications as well.
INSAT-4E will have five C x S transponders each of 9 MHz bandwidth and five S x C transponders each of 2.7 MHz bandwidth which will together cover the entire country.
What is S-DMB?
To simplify - S-DMB or Satellite based Digital Multimedia Broadcasting is a digital radio transmission technology developed in South Korea as part of the national IT project for sending multimedia such as TV, radio and datacasting to mobile devices such as mobile phones, laptops and GPS navigation systems. S-DMB is intended to deliver multimedia content to mobile handsets. The system can deliver real-time streaming TV-programs and multimedia services as well as non real-time push and store multimedia services to mobile users.
In 2005, South Korea became the first country in the world to start S-DMB service. Countries with S-DMB standards include -
(01) CMMB (China Mobile Multimedia Broadcasting) – China
(02) DVB-SH (Digital Video Broadcasting - Satellite for Handhelds) – European Union & United States
(03) S-DMB (Satellite Digital Multimedia Broadcast) – South Korea
With the launch of INSAT-4E/GSAT-6, India will be the fourth country (EU excluded) in world to indigenously deploy Satellite based Digital Multimedia Broadcasting which can be very well used for other social and strategic applications as designated by the government of India back in 2011.
Military & Strategic Applications Payloads on-board INSAT-4E -
India is using it's geosynchronous satellites that is the GSAT series for its Ballistic Missile Defence project - by arming them Electronic Intelligence System (ELINT) Packages to track electromagnetic emissions from geostationary orbits - GSAT 7 - India's first Military Satellite and GSAT-16 are the best examples to come up with such sophisticated packages. The original GSAT series satellites are to be replace with these new ones with ELINT packages as soon as the original ones complete their respective life cycles.
The project is aimed at installing sensitive surveillance equipment along with other payload on the G-sats. They will capture the signature of any missile launch activities happening in a radius of 6,000 km.This signature will be transmitted to a central control unit which would initiate necessary counter-mechanism.
Next-Gen GSAT series satellites are equipped with a MIL-SATCOM payload plus a ballistic missile warning system sensor for BMD.
India to use geo-stationery satellites for missile defence - The Times of India
Saurav Jha's Blog : GSAT-7 bolsters Indian Navy's Network Centric Warfare (NCW) capability
India's GSAT-16 Satellite with Electronic Intelligence System (ELINT) Package all set for Launch!
Technological Breakthroughs for INSAT-4E -
>> The greatest challenge envisaged by ISRO was the deployment of 6.5 metre antenna in a rocket envelope, which cannot accommodate anything greater than 2.5 metre in girth. It was then that the concept of folding the antenna like an umbrella was designed. The folded umbrella would be placed in the rocket and unfurled in the orbit after the satellite was in position. What more, building the antenna system with perimeter truss consisting of composite tubes to support the front and rear webs with fibre reinforcement was attempted for the first time.
>> Graphite or epoxy tubes connected by hinges that allow the furled antenna were to be stowed for launch to fit within the rocket fairing. Pyro-initiated release mechanisms were required to open launch restraints before the antenna gets deployed. This also involved development of highly accurate, synchronous and agile actuation system.
>> Another technological challenge for ISRO scientists was to raise the power onboard the satellite, four to five times the normal limits, to enable the omni-directional high-powered spot beam transmission and there was also the challenge of shrinking the bandwidth to a great extent.
>> When a satellite system is required to communicate with a very small earth receiver such as handheld mobile phone or a moving automobile-based unit, the flux density of the signal received should be of a high order. This provides a high quality Satellite Digital Multimedia Broadcasting (S-DMB) link. To achieve this, satellites usually operate on S-Band and provision is made for a combination of high power amplifiers and a large aperture reflector antenna on the satellite. A 6.5 metre projected aperture paraboloid reflector has been used on the GSAT-6 satellite to achieve high beam directivity over the desired coverage regions.
>> While GSAT-6 is designed to provide digital CD-quality audio, TV-quality video and data broadcasting services to the country, the radiation pattern was designed to be carefully controlled to avoid interferences with other Asiatic regions.
>> While conceiving this ingenious satellite, the scientists came across two major design challenges: one, the packaging of the stowed structure and two, controlling the reaction caused by the unfurled structure when operating in the orbit.
>> Extensive ground tests were carried out on the satellite system to ensure proper functioning. An acceptable process coupled with test results and analysis needs was developed to predict antenna performance, since direct measurement of the antenna radiation pattern of large aperture is impractical.
>> The Government of India approved the project of design, development and launch of GSAT-6/INSAT-4E to provide Satellite Digital Multimedia Broadcasting (S-DMB) at a total estimated cost of Rs. 269 crores with a foreign exchange component of Rs. 102 crores. The project provided a platform for technology demonstration of large unfurlable antenna in spacecraft, handheld ground terminals and large network management systems.
which military branch will use this satellite?? army or air force??
It will be operated by National Technical Research Organisation (NTRO) though it will also be used for civilian purposes as well - It is not a dedicated military communication satellite as in the case of GSAT-7 (India's first and Indian Navy's dedicated military communication satellite) and GSAT-7A (IAF's dedicated military communication satellite). There is no dedicated military satellite planned for the Indian Army which will continue to use civilian and GSAT-7/GSAT-7A satellites for it's Network-centric warfare capabilities.
