The Evolution of the Two Standards of Measure to the Present Day Electromagnetic Distance Measurements (EDM)

[摘要] Distance measurement has developed through history from preChristian times when the basic unit was cubit up to thepresentday use of automated distance measuring instruments by surveyors, which makes measurements rapid and easy. The accuracy of distance measurements depends, on the calibration of the measurement unit and since the modulation wavelength is used as ameasurement unit in electronic distance meters, this wavelength has to be accurately established. Since most surveyors do not know the basic checks for calibration of today’s EDM instruments they are not able to achieve the accurate results required. This paper looks at the origin and development of the two standards of measure to the presentday use of wavelengths of radiation for defining a standard; also step by step routine checks for the calibration of the EDM are provided. CONTACT E. E. Duncan, Peter Ekow Baffoe and F. BilsonDarku Geomatic Engineering Dept. Western University College Department of Geodetic Engineering KNUST, WUC, Geomatic Engineering P.O. Box 237 Tarkwa GHANA Tel. + 233 362 21139 /20324 Fax + 233 362 20306