What is an optical satellite?
Satellites with optical sensors generate images of the Earth over relatively large areas and are useful in the production of vegetation maps or to estimate specific vegetation parameters. These wavelengths are useful for distinguishing between forest types and other vegetation classes.
How optical communication is used in satellite networks?
Satellite communication uses electromagnetic waves as a medium for propagation. Optical communication uses the light rays as a medium of propagation. In satellite communication, satellites as a relay station are used for communication.
Why do we use satellite communication?
The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated geographical points. Communications satellites use a wide range of radio and microwave frequencies. This allocation of bands minimizes the risk of signal interference.
How many satellites are needed for global communication?
For a world-wide communication between any two locations of the earth, minimum 3 satellites must be placed such that each pair of the satellites subtend angle of 120o at the centre of earth.
What are the four main uses of artificial satellites?
Artificial satellites can be used for:
- communications – satellite television and phone calls;
- Earth observation – including weather forecasting, tracking storms and pollution, spying and satellite photography;
- navigation – including the Global Positioning System (GPS);
What are the five uses of artificial satellite?
The uses of artificial satellites are:
- Communication – The geostationary satellites are used for communication purposes like long distance telephone calls, telex, radio , T.V broadcasts etc.
- Spying.
- Weather forecasting.
- Collecting information about outer planets and outer space.
What are the 2 types of satellites?
There are two different types of satellites – natural and man-made. Examples of natural satellites are the Earth and Moon. The Earth rotates around the Sun and the Moon rotates around the Earth. A man-made satellite is a machine that is launched into space and orbits around a body in space.
How many satellites are in orbit right now?
However in 2021, almost 850 satellites have been launched as marked by the end of April, which is 66.25% of 2020….Causes for the growth in the number of satellites.
| Number of satellites | Main purpose |
|---|---|
| 104 satellites | Space science and observation |
| 20 satellites | Earth science |