Uncertainty evaluation of trigonometric method for vertical angle calibration of the total station instrument

• Easy to perform trigonometric method for the calibration of a total station is proposed.
• The measurement uncertainty evaluation algorithm of proposed method is analyzed.
• The experimental results are presented and compared.

The total station is an instrument, widely used in civil and environmental engineering, for flat and vertical angle as well as distance measurements. Typically, routine calibration of such an instrument is obligatory, and depending on the local regulations, is performed typically annually or bi-annually. Analysis of previous research shows that undertaking flat angle calibration under laboratory conditions is more common than calibration of vertical angle measuring systems. This paper deals with a trigonometric vertical angle calibration method and research into determining the main sources of uncertainty is described in the paper. The principle of the method is explained, as well as the uncertainty evaluation based on GUM and the advantages as well as the weaknesses of the setup are discussed.