ABSTRACT
In remote sensing, various sensors are used to measure in a given wavelength band the radiance of objects under study. Conventionally two types of sensors, viz., active and passive, are employed. Scanning is carried out by means of a rotating or oscillating mirror, inclined at 45° on the vertical and situated perpendicular to the direction of motion of the platform. The geometry of whiskbroom scanners should be fixed precisely since it affects the restoration and rectification of images. The pushbroom or along-track scanner system is more recent and uses no scanning mirror. An inverse proportionality exists between geometric resolution and spectral resolution. The plane of the elliptical orbit is known as the orbital plane of the satellite. The angle between the orbital plane and the equatorial plane defines the angle of inclination of the satellite. A geostationary orbit is one in which the satellite is always situated at the zenith of a point above the Earth's equator.
