DETERMINATION OF AIR REFRACTION INFLUENCE ON TRIGONOMETRIC HEIGHT DIFFERENCES

Abstract

Efficiency of trigonometric levelling method for height differences determination is better than those
determined by geometric levelling but its accuracy is significantly lower. Development of accuracy of
geodetic instruments increases possibilities for improvement accuracy of trigonometric
levelling.However, air refraction appears as ultimate limitation factor for accuracy of trigonometric
heights determination improvement. This paper aims to research the influence of air refraction on
accuracy of height differences determined by trigonometric levelling method. Basic statistical
hypothesis is that influence of air refraction on height differences is negligible. The case study is based
on the results of regular measurements on “Vlasina” dam by using results of geometric and
trigonometric levelling.