SYNCHRONOUS AND SUN-SYNCHRONOUS
satellites are the satellites which revolve round the earth above the equatoratthe
height of about 36,000 to 41,000km., in
the direction of earth's rotation. They make one revolution in 24hours,
synchronous with the earth's rotation (Fig.2). As a result,
it appears stationary with respect to earth.
These platforms always cover a specific area and give
continuous coverage over the same area day and night. Their coverage is limited
to 70 N and 70 S latitudes and one satellite can view one third globe. These are mainly used for communication and weather
monitoring. Some of these satellites are INSAT, METSAT and ERS series.
round the earth in north-south direction (poleto pole) at the height of about 300to1000
km. (Fig.2.1) they pass over places on earth having the same latitude twice in
each orbit at the same local sun-time, hence are called sun-synchronous
satellites. Through these satellites, the entire globe is covered on regular
basis and gives repetitive coverage on periodic basis. Alltheremotesensing resources
satellites may be grouped in this category. Few of the sesatellites are: LANDSAT,
IRS, SPOT series and NOAA, SKYLAB, SPACE SHUTTLE etc.