This bachelor’s thesis deals with determining the quasigeoid course in the central part of the city of Brno using a combination of GNSS technology and technical levelling. The theoretical part focuses on height systems, reference surfaces, the fundamental levelling network of the Czech Republic, and the principles of GNSS RTK measurements and technical levelling. The practical part includes reconnaissance of the study area, establishment of an auxiliary surveying network, implementation of GNSS measurements, and determination of height differences between auxiliary and levelling points. The measured data were subsequently processed, transformed between the Bpv and ETRS89 systems, and used to create a model of the quasigeoid course in the investigated area. The result of the thesis is a digital model and profile illustrating the quasigeoid course in the central part of Brno and an evaluation of the accuracy of the applied measurement methods.