How does the Radar Altimeter determine the height of the aircraft?

The radar altimeter determines the height of the aircraft by timing the signal bounce from the ground. This system uses radar waves, sending a signal down toward the ground and measuring the time it takes for the signal to return after bouncing off the surface. By calculating the elapsed time and knowing the speed of the radar signal, which travels at the speed of light, the system can accurately determine the distance to the ground and, therefore, the altitude of the aircraft above the terrain.

This method provides precise measurements of altitude, particularly useful in low-flying situations or when flying at varying elevations. Radar altimeters are essential for ensuring safe landings and takeoffs, especially in poor visibility conditions, where other altitude measurement methods may not be reliable.