Satellite Based Education for Distance Learning through EDUSAT

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Satellite communication technology using EDUSAT is a strong tool for the development of distance education
The students visualize the teaching and methods from the video programs delivered through EDUSAT.

  • Students gain knowledge and understanding of their subjects and they can clarify their doubts then and there.
  • The objective of information and communication technology by using EDUSAT has to bring quality education from primary to higher, technical and professional education to the unreached poor people of the country.


Electronic Learning (e-Learning)

  • Electronic Learning (e-Learning) is a type of education system where the medium of instruction (Teaching and Learning) is through computer. EduSat is a satellite designed by ISRO and it is exclusively devoted to the field of education.
  • E-Learning refers to the use of networked Information and Communication Technology (ICT) in teaching, delivering and learning in education anytime and anywhere.
  • E-Learning is a broad set of applications and processes which includes web-based learning, computer based learning, multimedia learning, online learning and virtual learning.

Information Communication Technology

  • Information Communication Technology also known as ICT is a commonly referred to branch of Engineering.
  • It involves the use of computers and software to operate and manage information. ICT deals with storage, data transmission, manipulation of data and retrival. Information Communication Technology uses computers and computer networks in various fields including education.
  • It also includes other technologies that are used to distribute communication and information through telephone, television, mobile phone, multi-media, bluetooth and other telecommunication equipments in general.
  • Various scientific and technological applications like mobile communications, Direct-to-Home services, meteorological observations, telemedicine, tele-education, disaster warning, radio networking, search and rescue operations, remote sensing and scientific studies of the space are also included.
  • Broad definition of the field of e-learning includes the use of technology to deliver learning and training programs such as CD-ROM, Internet, Intranet, wireless and mobile learning.
  • Some include Knowledge Management as a form of e-Learning.


Satellite communication:

  • The satellite had the benefit of radiatively cooled Ku-band Travelling Wave Tube Amplifiers (TWTAs) and dielectrically loaded C-band Demultiplexer for its communication payloads.
  • Satellites can establish connectivity between urban educational institutions and a large number of rural and semi-urban educational institutions to provide an educational infrastructure.
  • With the success of the INSAT based educational services in the eighties, a need was felt to launch a satellite dedicated for educational service and the ISRO conceived the EDUSAT Project in October, 2002.

Satellite Working Principles

  • A satellite works by receiving radio signals sent from the Earth and resending the radio signals back down to the Earth.
  • In a simple system, a signal is reflected, or "bounced," off the satellite. For example, it is possible to bounce a signal off the surface of the Moon back down to Earth.
  • Because the Moon is very far away, for this to work the signal from the Earth must be very strong and the receiver receiving the signal must be sensitive enough to detect the very weak signal receive back from the moon.
  • Geosynchronous orbiting satellites, those located 36,000 kilometers above Earth, are mainly used for fixed satellite services, namely for broadcasting and for communication. INSAT (Indian National Satellite System) is an example of such satellite.
  • Currently, INSAT-2B, 2C, 3B and EDUSAT operate from this orbit.
  • In satellite communication, signal transferring between the sender and receiver is done with the help of satellite. Satellite communications play a vital role in the global telecommunications system. Approximately 2,000 artificial satellites orbiting Earth relay analog and digital signals carrying voice, video, and data to and from one or many locations worldwide.
  • There are three types of communication services that satellites provide:
  1. Telecommunications
  2. Broadcasting, and
  3. Data communications.

Telecommunication services include alls and services provided to companies, as well as wireless, mobile, and cellular network providers.

Broadcasting services include and television delivered directly to the consumer and mobile broadcasting services.

Data Communications involve the transfer of data from one point to another. Corporations and organizations that require financial and other information to be exchanged between their various locations use satellites to facilitate the transfer of data through the use of Very Small-Aperture Terminal (VSAT) networks. With the growth of the Internet,[1] a significant amount of Internet traffic goes through satellites, making ISPs one of the largest customers for satellite services.


  • To date, India has used both its multi-purpose INSAT satellites to provide long-distance education information alongside their telecommunications, broadcasting and weather-forecasting functions.

Sfig2.jpg Coordination of Satellite Communication Network.

Sfig3.jpg Satellite Communication Module

  • Unlike a passive satellite such as the moon or the early ECHO satellite, a modern communications satellite receives the radio signal and sends it back down to Earth stronger than it was received. This process is called "amplification" of the radio signal.
  • People communicate to a satellite using an antenna on the ground, which called an "earth station" in technical terms. The earth station sends up radio signals to the satellite.
  • GSAT-3, known as EDUSAT is meant for distant class room education from school level to higher education. This is the first dedicated "Educational Satellite" that provide the country with satellite based two way communication to class room for delivering educational materials.
  • The Indian National Satellite (INSAT) system which are placed in Geo-stationary orbits is one of the largest domestic communication satellite systems in Asia-Pacific region. INSAT space segment consists of 24 satellites out of which 10 are in service (INSAT-3A, INSAT-4B, INSAT-3C, I NS AT - 3E, KA LPANA- 1, I NS AT - 4A, I NS AT - 4CR, GSAT-8, GSAT-12 and GSAT-10)
  • The system with a total of 168 transponders in the C, Extended C and Ku-bands provides services to telecommunications, television broadcasting, weather forecasting, disaster warning and Search and Rescue operations.
  • In satellite communication, signal transferring between the sender and receiver is done with the help of satellite.


In case of direct live transmissions, all the connected Centers work in two-way interactive modes where the receivers directly interact with the expert and get clarified immediately. They use Satellite Interactive Terminal (SITs) that cost around USD 6000 approximately.

In case of Receive Only Terminal (ROTs) the users receive the transmission but not are able to interact with the experts and costing around USD 1500 per terminal.

EDUSAT provide wide range of educational delivery modes like one way TV broadcast, interactive TV, Video conferencing, computer conferencing, web-based instructions, etc.

  • So far, 70 broadcast and interactive networks have been setup, out of which 10 networks use national Ku-band beams and the remaining networks are on regional Ku-band and extended-C band national beams.
  • Live video streamed output generated using public domain free multimedia player, encoder and streamer software VLC (Video LAN Client) and transmitted through EDUSAT national beam network.
  • The universities / technical institutions (classrooms) equipped with EDUSAT SITs/ ROTs receive the programs through an Internet Protocol (IP), played with VLC player and projected it with LCD for the benefit of many students.
  • Interactive sessions are being followed by the live lecture / practical demo using Microsoft Net meeting that supports audio and video.
  • Most of the Distance Learning environments are static nature with limited live and interactive activity and whereas this program is completely live and most effective way of interaction and therefore it is unique and innovative.

Scope of e-Learning in India

E-learning can be examined at two levels. The first one is education and another one is training. The education can be used at both elementary and higher levels. In training it can be used by Institutes / companies to train and upgrade their employees.

Looking at the population, the available universities are not enough to accommodate all the people seeking education. At this point distance education comes in and has already been quite popular. E-learning can play a major role even here.

Advantages of e-Learning

  • There are a number of advantages of e-learning.
  • First, we are using state-of-the-art technology and instructional strategies.
  • Cultures can be shared through e-learning. Disabilities can be accommodated, with or without the knowledge of other participants.
  • Gender may not be an issue, because in many situations, gender is unknown – or it can be.
  • Because of global access, the classroom may be the world.
  • Nothing can replace traditional classroom teaching, but e-learning complements the process and can help reach out to the masses.
  • The biggest advantage of e-learning lies in its ability to cover distances. For an organization that is spread across multiple locations, traditional training becomes a constraint.
  • All trainees need to come to a classroom to get trained.
  • Additionally, the trainee’s learning pace is not addressed as all trainees are treated as having equal abilities and there is little flexibility in terms of timing and completion of the course.
  • The major advantage is the consistency that e-learning provides. e-learning is self-paced, and learning is done at the learner’s pace.
  • The content can be repeated until it is understood by the trainee.

EDUSAT carries five Ku-band transponders providing spot beams that will focus on specific regions, one Ku-band transponder providing a national beam and six extended C-band transponders with national coverage beam.

Sfig4.jpg Potential Use of Educational Satellite

  • One of the common disadvantages to e-learning is that some students, especially those for whom English is not their native language, have difficulty communicating and being understood. Another group of students may experience computer or technology anxiety, which may in turn impact their learning and their final grades.

EDUSAT Application Technology

The DVB-RCS system supports communication channels that operate in two directions: a forward channel from the hub station to many terminals and a return channel from each terminal to the hub station.

Satellite Interactive Terminal (SIT)

A Satellite Interactive Terminal is a user terminal with the capability to communicate via a return channel. A typical SIT with 1.2 m antenna for low data rates can be a connecting device into a computer or TV set for interaction. Satellite interactive terminal for high data rates with 1.8 m antenna can be used for video conferencing.

SITs can be connected to several user PCs via a Local Area Network (LAN). EDUSAT is presently configured for 10 Mbps on the Forward Link considering satellite resources available and total traffic expected among all the SITs. Table 1 presents the Installation, Commissioning and Integration of S.I.T\’s in education.

Receive Only Terminal (ROT)

  • The receive only terminal (ROT)3, is a passive communication device making no provision for interactivity. In the EduSat context, such terminals are 0.75 meter dish antennas used for one-way TV and data reception.
  • Each user agency in EduSat can establish its own independent Wide Area Network (WAN), but will be expected to use TCP/IP protocols for communication.
  • Video conferencing can be initiated from the TE to achieve direct interactions between the teacher and students. The student database will be maintained there, as well as such administrative support as online registration, online examination, distribution of circulars and announcements.
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