This thesis presents a process of geodetic network establishment for testing GNSS-RTK instruments. The worksite was located at the car fair in Ljubljana. The objective of the thesis was to get coordinates of points, stabilised within a few meters. Moreover, we present theoretical background as well as practical tests of GNSS-RTK instruments according to ISO 17123-8 standard. Two instruments, namely JAVAD TRIUMPH-LS and Leica VIVA GS15, were included into tests. The added value of the specific worksite is in possibility of testing three instruments simultaneously to find out and compare their operation under the same conditions.