The altimeter is an instrument which measures vertical distance with respect to a reference level. The altimeter is an instrument that measures the altitude of the land surface or any object such as an airplane. Louis Paul Cailletet was the French physicist who invented the altimeter and the high-pressure manometer.
Louis Paul Cailletet (1832-1913)
French physicist and inventor who
in 1877-78 was the first to liquefy oxygen, hydrogen, nitrogen, and air.
Barometric
Altimeter
In 1928, German inventor Paul Kollsman
changed the world of aviation with the invention
of the world's first accurate Barometric Altimeter also called the Kollsman
Window.
Radio Altimeter
Lloyd Espenschied invented the first
radio altimeter in 1924. In 1938, the fm radio altimeter was first demonstrated
in New York by Bell
Labs. In the first public display of the device, radio signals were
bounced off the ground, showing pilots the altitude of an aircraft.

