What is remote sensing: definition, types ... (1/3)

    Most of us know that all the messages we send and calls we do everyday, and all what is linked to telecom is done using satellites. However, most of us ignore another fundamental aspect of satellites! It is the remote sensing by satellites.

    Remote sensing is a technique allowing to have and extract information of an area without touching it. How can we do this?

    We already said that the biggest part of remote censing is done by satellite. Those satellites are equiped by sensors and transmittors of electromagnetic radiation to sweep the area. After arrival to the object in the area, it reflects a part of electromagnetic radiation and captured by the sensor. 

    Let's think about the example of human vision as an example of biological remote sensing, the light coming from the sun arrives on the objects of the surface, those objects reflect a part of solar radiation and it is captured by our eyes playing the role of a biological sensor.

    There are two types of sensors:

• Active sensors: they transmit their own electromagnetic radiation and capture it after reflection. They have the ability to work even in the night.

• Passive sensors: they use the radiation of the sun and capture its reflexion. Because they are based on solar radiation, they can’t function at night.