Altimeter

Source: Wikipedia, the free encyclopedia.
Not to be confused with attitude indicator.
inHg
(1013 hPa) is showing in the Kollsman window

An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level.[1] The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water.

Types

Pressure altimeter

This section is an excerpt from Pressure altimeter.[edit]
Digital barometric pressure sensor for altitude measurement in consumer electronic applications
Altitude can be determined based on the measurement of atmospheric pressure. The greater the altitude, the lower the pressure. When a barometer is supplied with a nonlinear calibration so as to indicate altitude, the instrument is a type of altimeter called a pressure altimeter or barometric altimeter. A pressure altimeter is the altimeter found in most aircraft, and skydivers use wrist-mounted versions for similar purposes. Hikers and mountain climbers use wrist-mounted or hand-held altimeters, in addition to other navigational tools such as a map, magnetic compass, or GPS receiver.

Sonic altimeter

In 1931, the US Army Air Corps and General Electric tested a sonic altimeter for aircraft, which was considered more reliable and accurate than one that relied on air pressure when heavy fog or rain was present. The new altimeter used a series of high-pitched sounds like those made by a bat to measure the distance from the aircraft to the surface, which on return to the aircraft was converted to feet shown on a gauge inside the aircraft cockpit.[2]

Radar altimeter

Main article: Radar altimeter
Piper PA-28
is seen on the top row of instruments, second from right

A

combat aircraft
to fly at very low height above the terrain.

After extensive research and experimentation, it has been shown that "phase radio-altimeters" are most suitable for

ground effect vehicles, as compared to laser, isotropic or ultrasonic altimeters.[3]

Laser altimeter

Lidar technology is used to help navigate the helicopter Ingenuity on its record-setting flights over the terrain of Mars by means of a downward-facing Lidar altimeter.[4]

Global Positioning System

augmentation.[5] In hiking and climbing, it is common to find that the altitude measured by GPS is off by as much as 400 feet (122 metres) depending on satellite orientation.[6]

See also

References

  1. ISBN 0-85045-163-9
    .
  2. ^ "Meter Gives Elevation", Popular Science, March 1931
  3. ^ Nebylov, Prof. Alexander and Sharan Sukrit. "Comparative Analysis Of Design Variants For Low Altitude Flight Parameters Measuring System". 17th IFAC Symposium for Automatic Control.
  4. ^ "How NASA Designed a Helicopter That Could Fly Autonomously on Mars". IEEE Spectrum. 17 February 2021. Archived from the original on 19 February 2021. Retrieved 19 February 2021.
  5. PMID 28813023
    .
  6. ^ "Understanding the Accuracy of the GPS Elevation Reading". Garmin. Archived from the original on March 5, 2020. Retrieved March 14, 2020.

External links

Wikimedia Commons has media related to Altimeter.
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