Principle
Remote sensing is the acquisition of information about an object without coming in physical contact of
that object. And ‘sensor’ is a device that helps in gathering of information (amount of EMR emitted or
reflected by the object). In other words, ‘sensor’ is the remote sensing device that records wavelengths
of energy. Generally, these sensors are mounted or fixed with a ‘platform’. Therefore, ‘platform’ is
termed as a vehicle that carries remote sensing device.
Indian Satellites and Sensors characteristics:
IRS satellite program Indian Remote Sensing (IRS) satellite system is one of the largest civilian remote
sensing satellite constellations in the world used for earth observation. Objective of the program is to
provide a long-term space-borne operational capability for the observation and management of the
natural resources. IRS satellite data have been widely used in studies related to agriculture, hydrology,
geology, drought and flood monitoring, marine studies and land use analyses. The first satellite of the
mission IRS-1A was launched in 1988.
IRS satellites orbit the Earth in sun-synchronous, near-polar orbits at low altitude. Various missions in
the IRS satellite program employ various sensors viz., LISS-1, LISS-2, LISS-3, WiFS, AWiFS etc.
A list of the sensors that have been used in Indian Remote Sensing satellites Follows.
Satellite Microwave Radiometer (SAMIR)
SAMIR was the payload for BHASKAR I and II satellites launched in 1979 and 1981. They successfully
provided data on the sea surface temperature, ocean winds, moisture content over the land and sea.
It was a dicke type radiometer with a temperature resolution better than 1 degree kelvin.
Two Band T.V. Payload
The Bhaskara satellites I and II had a two band TV payload for land applications. It gave images of earth
from a height of 525 Km. The data were used in meteorology, hydrology, and forestry.
Smart Sensor: Rohini Rs-D2, (the successor to the failed Rs-D1) was launched on Apr. 1983. It carried a
Smart sensor, which was a 2-Band solid-state device. It had the first CCD camera developed in house.
