Anusat : The Anna University Microsatellite

ANUSAT is a 50 kg micro satellite being designed and fabricated at Anna University, Chennai. The aim is to bring university based academicians and research and development experts of ISRO together to implement a project in university environment. ANUSAT carries a digital store and forward payload for amateur communication. In addition, a number of technological payloads like digital receiver and turbo coder and MEMS based gyro and magnetic field sensor are planned to be in this micro satellite. During the year, the configuration of this satellite has been finalised and breadboard/design verification models of the core electronic systems completed.


ANUSAT, A micro-satellite designed and being built by Anna University at a cost of Rs.5.5 crores. The Indian Space Research Organisation (ISRO), sponsor of the project, would decide the launch of the micro-satellite.This collaboration is the first of its kind in India. Mr Rajaram Nagappa, a fellow MITian, former ISRO scientist and the Chief of Centre for Aerospace Research, MIT is the key interface person between the ISRO experts and the academic community.

Students and Professors from various departments have been actively involved in this project for almost an year now. At present various subsystems of power electronic systems, the BUS electronic and RF systems have been developed.

ISRO's Polar Satellite Launch Vehicle(PSLV) at Sriharikota has launched the micro-satellite, first of such satellite to be built by any university in the country. Dr. Jayaraman said Anusat would have a "store and forward" payload. The control centre would be on the Madras Institute of Technology campus while three ground stations would be located in Bangalore, Guwahati and Pune.

The Radar Imaging Satellite : RISAT

The PSLV-C12, carrying 300-kg Radar Imaging Satellite (RISAT-2) and 40-kg Micro Satellite ANUSAT lifted off from ISRO’s Satish Dhawan space Centre from Sriharikota on Monday 20 April 2009 .

At the end of the 48-hour countdown, the 44-meter tall four-stage PSLV-C12 blasted off from the second launch pad with the ignition of the core first stage.

The Polar Satellite Launch Vehicle, weighing 230 tonnes at the time of launch, soared into a clear sky at 6.45am(local time) from the spaceport here, about 90 km north of Chennai.

This is the 15th flight of ISRO’s workhorse PSLV, which had launched 30 satellites (14 for India and 16 for foreign countries) into a variety of orbits since 1993.

The launch vehicle carries two payloads - RISAT-2 (with all weather capability to take images of Earth) and ANUSAT (the first satellite built by an Indian University to demonstrate the technologies related to message store and forward operations).

The rocket would place both the satellites in their orbits around the earth shortly.

What’s RISAT?

RISAT is the first satellite imaging mission of ISRO (Indian Space Research Organization) using an active radar sensor system, namely a C-band SAR (Synthetic Aperture Radar) imager, an important microwave complement to its optical IRS series observations missions. The overall objective of the RISAT mission is to use the all-weather as well as the day-and-night SAR observation capability in applications such as agriculture, forestry, soil moisture, geology, sea ice, coastal monitoring, object identification, and flood monitoring.


RISAT is a newly developed agile spacecraft, featuring a multi-mode and multi-polarization SAR system in C-band, providing spatial resolutions in the range of 3-50 m on swath widths ranging from of 30-240 km.

Spacecraft:

The spacecraft bus consists of a prism shape build around a central cylinder. Most of the spacecraft subsystems and the complete payload are integrated in the prism structure and the central cylinder. The spacecraft is 3-axis stabilized, developed, manufactured and integrated by ISRO/ISAC, Bangalore, India. The solar panels and some subsystems are mounted on the cuboid portion of the spacecraft. Two solar panels with high efficiency multijunction solar cells provide the S/C power; they are charging two sets of NiH2 batteries, each with a capacity of 40 Ah. Both energy sources deliver 3.5 kW of sustained DC power at 70 V regulated voltage to the payload for 10 minutes duration in each orbit. The on-orbit total spacecraft mass is about 1750 kg with about 950 kg of SAR payload mass.


Designed by the Israeli Aerospace Industries, RISAT can take images through the thickest cloud cover, rain, snow or fog conditions during night and day.

While the RISAT will be used extensively for purposes like mapping, managing natural disasters and surveying the seas, it can also see through camouflage like cloth or foliage used to conceal camps or vehicles.

RISAT will enable India to keep a watch on terror camps, military installations across boundaries, missile sites and suchlike.
However, RISAT is not India’s first spy satellite. The Technology Experiment Satellite has been used for photo-reconnaissance since 2001.

But unlike previous remote sensing satellites, RISAT is the first with a synthetic aperture radar, which gives it a day-night, all-weather snooping capability.

It should also help keep track of ships at sea that could pose a threat.
The RISAT will reduce India’s dependence on foreign suppliers like Ikonos for satellite imagery. But many more gaps need to be plugged. Despite the desperate need, India is still awaiting a dedicated military satellite

Satellite Internet

As Internet traffic continues to grow at exponential rates worldwide, Internet services providers (ISPs) everywhere are faced with the challenge of keeping up with demand for network bandwidth and developing creative solutions for squeezing more use out of existing bandwidth.

Satellite communication has the unique ability to deliver bandwidth exactly where and when it is needed, irrespective of geography and local infrastructure.
Depending on the location and needs, Internet via Satellite is the best method for either by-passing or extending the terrestrial fiber optic network.

Internet via Satellite is therefore becoming the natural high speed transport medium for a wide range of IP and multimedia applications the world over, whether for consumer or business applications - and at speeds of 2 Mbit/s per user for Internet access and at up to 40Mbit/s per transponder for services such as data broadcasting.


How do you access the Internet other than dial-up if you live too far from a phone company office for DSL and there is no cable TV on your street? Satellite Internet access may be worth considering. It's ideal for rural Internet users who want broadband access.

Satellite Internet does not use telephone lines or cable systems, but instead uses a satellite dish for two-way (upload and download) data communications. Upload speed is about one-tenth of the 500 kbps download speed. Cable and DSL have higher download speeds, but satellite systems are about 10 times faster than a normal modem.

Firms that offer or plan to offer two-way satellite Internet include StarBand, Pegasus Express, Teledesic and Tachyon. Tachyon service is available today in the United States, Western Europe and Mexico. Pegasus Express is the two-way version of DirecPC.

Two-way satellite Internet consists of:

* * Approximately a two-foot by three-foot dish
* * Two modems (uplink and downlink)
* * Coaxial cables between dish and modem

The key installation planning requirement is a clear view to the south, since the orbiting satellites are over the equator area. And, like satellite TV, trees and heavy rains can affect reception of the Internet signals.
Two-way satellite Internet uses Internet Protocol (IP) multicasting technology, which means up to 5,000 channels of communication can simultaneously be served by a single satellite. IP multicasting sends data from one point to many points (at the same time) by sending data in compressed format. Compression reduces the size of the data and the bandwidth. Usual dial-up land-based terrestrial systems have bandwidth limitations that prevent multicasting of this magnitude.

Some satellite-Internet service still requires you to have a dial-up or cable modem connection for the data you send to the Internet. The satellite data downlink is just like the usual terrestrial link, except the satellite transmits the data to your computer via the same dish that would allow you to receive a Pay-Per-View television program.

So, if you are in a rural area and you want broadband access to the Internet, satellite Internet may be for you!