Engineering:Geodimeter

From HandWiki
Operator controls and sight of a Geodimeter

The Geodimeter (acronym of geodetic distance meter) was the first optical electronic distance meter surveying instrument.[1][2] It was originally developed for measuring the speed of light.[3][4] It was invented in 1947 by Erik Osten Bergstrand (sv) and commercialized in 1953 by the AGA (Aktiebolaget Gasaccumulator) company of Sweden.[5][6] It was used in the Transcontinental Traverse.

The Geodimeter business was acquired by SpectraPrecision which was acquired by Trimble Inc.[citation needed]

Electronic mechanism

The mechanism uses a Kerr cell in an optical train that chops a collimated beam of light under the control of a precision electronic oscillator in the megahertz range.[7] It is similar in principle to the mechanical chopper in Fizeau's measurement of the speed of light in air that used a toothed wheel.[8]

See also

References

  1. Rüeger 2012, p. 15.
  2. Bergstrand 1952.
  3. Froome & Essen 1969.
  4. Bergstrand 1950.
  5. Laurila 1960, p. 194.
  6. "AGA Geodimeter". 2014-10-03. http://www.aga-museum.nl/page/aga-geodimeter-nasm-2a. 
  7. Poling 1959.
  8. "EDM (Geodimeter Model 2A)", Database: Physical Sciences Collection - Surveying and Geodesy (Smithsonian Institution), 4 August 2015, catalog number 1998.3094.01, https://amhistory.si.edu/surveying/object.cfm?recordnumber=748815, retrieved 2018-05-02 

Sources

Further reading

External links

  • AGA Geodimeter Model 6 (Going the Distance: A Photo Collection Illustrating the History of Distance Measurement Tools at the National Geodetic Survey)