DBPapers
DOI: 10.5593/sgem2017/22/S09.018

CALIBRATION OF FIELD LENGTH BASELINES USING LEICA AT401 LASER TRACKER

F. Dvoracek
Wednesday 13 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-02-7 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 22, 139-146 pp, DOI: 10.5593/sgem2017/22/S09.018

ABSTRACT

The paper reveals proposed techniques and measurement results obtained by employing Leica AT401 laser tracker into processes of calibration of field length geodetic baselines.
Firstly, testing of the available laser tracker in Research Institute of Geodesy, Topography and Cartography (RIGTC) is shortly introduced and the development of a user-programmed software ATControl is presented. Secondly, measurement methodologies used for calibrating Czech State Long Distances Meausuring Standard Koštice and National Geodetic Baseline Hvězda are outlined. Finally, results from 20 epochs from Koštice baseline and 6 epochs from Hvězda baseline are evaluated.
Leica AT401 proved to be a useable tool for calibrating field length baselines even if many problems with automated target recognition and measuring range occurred. Scale accuracy of the calibration was mainly dependent on temperature gradients and additive constant on the long-term stability of baseline’s points. Accuracy expressed as a standard deviations varied about (0.4-0.6) mm + 0.34 mm/km for both baselines.
EURAMET’s research project “Absolute Long Distance Measurement in Air” describes needs for development in this field. Employing laser tracker instruments is one of the new ways how to conventionally maintain field length baselines around the world. Reached accuracy is comparable to outputs of methodology used by Finnish Geospatial Research Institute (FGI) but the whole process with laser tracker Leica AT401 is significantly easier and faster comparing to traditional scale transfers with Kern Mekometer ME5000.

Keywords: field length baseline, calibration, laser tracker, Leica AT401, metrology