A sensor measuring flying height of the three methods

Sensors in modern life and work in an increasingly important role to play , and is also very involved in a wide range of areas . For example, in the aviation field , use the sensor to measure altitude , which means, according to different measurement principles can measure the altitude of different definitions .1, the use of radio waves to measure the reflection characteristic approach altitude , the altitude is measured and converted to the time measurement. Electromagnetic wave propagation in the air, the speed of light c , and can hit the ground reflection . Thus , mounted on the aircraft radio transmitter emitting the electromagnetic wave to the ground , the plane antenna of the receiver by the time of receiving the reflected wave △ t , △ t can be measured based on the aircraft 's altitude H.2 aircraft by the acceleration Positioning Sensor to measure linear acceleration of ground motion perpendicular to measure altitude3 , measured by Camshaft Position Sensor to measure atmospheric parameters altitude , atmospheric pressure in the gravity field , atmospheric density were increased and decreased with altitude , although the variation of each different , but all have to follow the law , then, can through the sensor to measure atmospheric pressure or to indirectly measure the atmospheric density altitude .