Equipment
Electromagnetic Distance Meter
How It Works
EDM instruments are available to measure distance using light and radio waves, and have been used in Australia since very soon after their invention. The distance is calculated either from the time difference between a transmitted pulse and a return pulse or the phase difference between a transmitted and a reflected beam of radiation.
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Electromagnetic distance measuring equipment use three different wavelength bands:
The accuracy of the measurement varies from type to type but is usually in the order of +0.005m + 1:10,000 x distance. |
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When an EDM is used together with an electronic theodolite, the combination function as a total station.