Methodology of calibration of vertical angle measurements

At the moment in Lithuanian there is no existing reglamentation dealing with calibration or testing of geodetic angle measuring instrumentation (as theodolites, tacheometers, laser scanners, laser trackers etc.) in full range of its angular measurements. Though calibration and testing of horizontal angle measurements can be performed by multiple methods, calibration of vertical angle measurements still is a serious problem. In the paper a review on possible methodology of calibration and testing of vertical angle measuring instrumentation (like tacheometers, laser scanners etc.) is given together with proposed principles and technical solutions for the calibration