Lecture EDM TheoryandConstantErrors

# Lecture EDM TheoryandConstantErrors - Lecture EDM Theory...

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Lecture: EDM Theory Lecture Notes Text Coverage: Wolf and Mikhail, 11 th Ed Ch 6: 17-22, 24 Problems: 23 - 31 How an EDM works: Carrier wavelength: λ c Modulation Frequency: fm Modulation Wavelength: λ m= Va/fm Speed of light in a vacuum: c Speed of light in air: Va = c/N Index of Refraction of air: N Phase shift measured d Effective wavelength λ eff = λ m/2 Effective phase shift d eff = d/2 ( this ranges from 0 up to λ eff) Basic formula for distance: d N D m + = λ 2 , or D = N*( λ /2) + d/2, or D = N* λ eff + d eff Use of multiple frequencies for resolving the integer ambiguity (count of N), by multiples of 10. Example: A distance known to be 3421.567 m is measured with a Total Station of modulation frequency of 15 Mhz. Show how the EDM in the total station telescope measured this line. With fm = 15 Mhz, the modulation wavelength is: λ m = c/fm = 20 m. The effective wavelength is: λ eff=10m, d eff ranges from 0 to 10m. With

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## This note was uploaded on 05/19/2011 for the course GEM 3330 taught by Professor Gibson during the Spring '11 term at University of Florida.

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Lecture EDM TheoryandConstantErrors - Lecture EDM Theory...

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