“…The radar level gauges not only prove the good metrological properties, but they show a number of practical advantages as well, such as safety, absence of any movable mechanical parts, and their capability to function under the adverse environmental conditions (fog, high temperature, high pressure, aggressive ambient conditions). The initiative to develop a measuring system for the calibration and verification of the radar level gauges came from their manufacturers and suppliers themselves Pekarčíková, 2014;Popovič, 2015). The automatic level gauges are rather often used also for measurements related with payment purposes, as the legally controlled measuring instruments under the Act on metrology (Motzer, 2000).…”