It is necessary for understanding the operation of this device to know and understand the properties that has our Earth’s atmosphere.
To begin the blanket of air that covers the whole earth is called atmosphere. It consists of different gases that are grouped in layers around the earth from its surface. The first of these layers and the one below is called troposphere.
The powerful force of gravity is responsible for maintaining this series of layers of gases adhered to the circumference of the earth’s crust. And again differentiated depending on the corresponding stratum pressure occurs.
In simple terms this pressure is produced by the column of air (gases) which supports a body or an object at a certain height. This term corresponds to the static pressure. Logically the greater the height at which object is maintained lower pressure will have to bear.
Another differentiating factor is the temperature that varies according to the layer or stratum of the atmosphere.
So there are three main factors controlling the operation based altimeter atmospheric pressure, air density and temperature.
In the atmosphere can distinguish the following important information: the differences in pressure and temperature, the extent of sea level, and the resulting density at this point.
It is vital to measure the exact altitude of an aircraft to avoid accidents between themselves or with the terrain.