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.

Operator controls and sight of a Geodimeter

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

• Laser rangefinder
• Lidar
• Tellurometer

References

1. Rüeger 2012, p. 15.
2. Bergstrand 1952.
3. Froome & Essen 1969.
4. Bergstrand 1950.
5. Laurila 1960, p. 194.
6. "AGA Geodimeter". AGA Museum. 2014-10-03. Retrieved 2020-09-24.
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, retrieved 2018-05-02

Sources

• Bergstrand, Erik (1950). "Velocity of Light". Nature. Springer Science and Business Media LLC. 165 (4193): 405. Bibcode:1950Natur.165..405B. doi:10.1038/165405a0. ISSN 0028-0836. S2CID 4281189.
• Bergstrand, Erik (1952). "Distance measuring by means of modulated light". Bulletin Géodésique. 24 (1): 243–249. Bibcode:1952BGeod..26..243B. doi:10.1007/BF02526937. ISSN 0007-4632. S2CID 121587208.
• Poling, Austin C. (1959). Geodimeter Manual. U.S. Coast and Geodetic Survey. Publication 62-2.
• Laurila, Simo (1960), "Geodimeter", Electronic Surveying and Mapping: Part 1, Fundamentals of Electronic Surveying, Institute of Geodesy, Photogrammetry and Cartography, The Ohio State University, pp. 194–203, hdl:2027/uiug.30112007333120, OCLC 58011617, retrieved May 6, 2021 – via HathiTrust
• Froome, K.D.; Essen, L. (1969). The Velocity of Light and Radio Waves. Academic Press. ISBN 9780122428500. Retrieved 2020-09-24.
• Rüeger, J.M. (2012). Electronic Distance Measurement: An Introduction. Springer Berlin Heidelberg. p. 15. ISBN 978-3-642-80233-1. Retrieved 2020-09-24.

Further reading

• Poling, Austin C. (April 1958), "The Geodimeter and Tellurometer", Journal of the Surveying and Mapping Division, American Society of Civil Engineers, 84 (1), doi:10.1061/JSUEAX.0000024
• Rimington, George Robert Lindsay (March 1956), "Introduction to the Geodimeter", Cartography, 1 (3): 120–124, archived from the original on 2015-06-29 – via Pandora Archive{{citation}}: CS1 maint: date and year (link)
• Smith, J.R. (1998), The History of Geodimeter (PDF), Sweden: Spectra Precision, 07-98 Publ. No. 571 710 000
• Wise, Paul (2014), NATMAP's Introduction of Electronic Distance Measuring to Australia - Sixty Years On, Government of Australia, archived from the original on 2018-02-26 – via Pandora Archive{{citation}}: CS1 maint: bot: original URL status unknown (link)

External links

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