Precision Measurement of Australian EDM Baseline using a He-Ne Laser Beat Distance Meter

Abstract

The baseline for Electronic Distance Meters (EDM) in the Commonwealth Scientific and Industrial Research Organisation (CSIRO) was measured with a distance meter made by the National Research Laboratory of Metrology (NRLM) which utilises an intermode beat of a Ire-Ne laser. The measurements were carried out at distances between 20 m and 649 m and a repeatability of ±0.3 mm was obtained in measurements of 649 m after correction for refractive index and cyclic error. The measurement results were compared with other measurements using high precision commercial instruments. The compatibility of long distance standards between Japan and Australia has been verified from the calibration results of the beat distance meter in the NRLM tunnel both before and after these measurements.