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Invention : Altimeter


Innovation Info
Inventor (s): 
Louis Paul Cailetet
Country (invented in): 
Year Invented: 
Image Credit: 
Main Image: 

Who invented Altimeter?

Altimeter was invented by French physicist Louis Paul Cailetet in 1880s.

When was the Altimeter invented?


When was the patent granted?

Russell C. Newhouse for his experiments which led to invention of radio altimeter obtained patent for his invention radio altimeter in 1937.

Who was the patent granted to on the Altimeter?

  •  Russell C. Newhouse


What is working principle of altimeter?

  • Altimeter works on the principle that the pressure altimeter is an aneroid barometer that measures the pressure of the atmosphere level where the altimeter is located, and presents an altitude indication in feet. The mathematical relationship that relates to altimeter is:

                                       z = (RT/gM).loge(po/p)
             z = height difference between the initial height and the measurement height,
             R = gas constant,
            T = temperature of the air measured in Kelvin,
            G = acceleration due to gravity,
           M = molar mass of the gas,
           po= atmospheric pressure at the initial height and
           p = atmospheric pressure at the measurement height.

  • The relationship is programmed in to a chip so the height difference between the initial and measurement height can be measured easily. Only after the altimeter is set done, it will be able to indicate the correct altitude.


How does the invention Altimeter help?

  • Altimeter is generally used as an altitude measuring device of an object at some fixed level.
  • They are normally used in air planes to tell the pilot how high above the sea level they are flying.
  • Altimeter used in planes is considered as barometer as it is  used to tell what the air pressure is.
  • Altimeter is used to measure air pressure. The higher you go in to the air the lower is the air pressure. Altimeter shows how high they are only at sea level it does not show how high the plane is when it is above the ground.
  • At the time of landing, a radar altimeter is used due to its increased precision. So these radar altimeters are used in terrain warning systems to alert aircraft if there is raising terrain or if the aircraft is too low.
  • Pilots use radar altimeters in all types of airplane navigation to land their planes smoothly.
External References