Principle and data analysis of vertical angle calibration of geodetic instruments

Many opto-electronic digital instruments, such as rotary encoders, theodolites, total stations, laser trackers, etc. are used in machine engineering and instrumentation, geodesy, surveying, robotics and other branches of industry. Most of optical-electronic geodetic measuring instruments consist, among the other elements, of the circular scales and angular transducers for angle determination in two perpendicular planes – horizontal and vertical. Accuracy of the instrument mostly depends on the accuracy of these means for angle measurement. Even if calibration of horizontal angle measurement instrumentation can be relatively easily solved implementing rotary tables of different constriction the calibration of vertical angle measurement instrumentation is still a very complicated and not easily solvable task. Here in this paper we present a review and some simple means and methods that can be used in the angle measurement metrology, especially in vertical plane angle calibration. The results of the experimental calibration with the brief errors analysis and possibilities of accuracy increase of tested instrument are also given