Altimeters - general
Altimeters are used in many cases, particularly the pilots, rock climbers and paratroopers. Thanks to them, you can read the height above sea level and even below the surface of the earth. The altimeters shall be divided into two main types...
Pressure altimeters
Inside the pressure altimeter is tightly closed metal box in the shape of the disk, in which there is a vacuum. The capsule walls are thin and pofalowane respectively so as to make it flexible and up vulnerable to deformation. The external pressure causes the walls of the capsule strain...
Radar altimeters
The simplest air radar altimeter is only a single antenna, which in turn assume the functions of receiving and broadcasting. Electromagnetic waves generated in the transmitter and then sent by the antenna are passed on at a speed of 300,000 km / s. When you reach the surface of the earth already, some of them is reflected back and reaches out to the aircraft...
FM altimeters
FM is a common abbreviation used in radio technology, which describes the modulation frequency. FM radar altimeters have, which does not send a single pulse, only a continuous electromagnetic wave, and the broadcasting and receiving antennas are independent. Transmitted signal is modulated so that its frequency is increasing at a known rate...
Accuracy
FM altimeters allow precise metering of up to 3 km over land and up to 6 km over water. This is because the water cleaner and gives a stronger reflection of electromagnetic waves of such frequencies. The accuracy was, however, varies between one and a half meters at high altitude, while the ceiling is at its lowest to highest 60 centimeters...
Altimeters
