Kinematic GNSS positioning is becoming increasingly important today, both in surveying through direct positioning of UAVs (Unmanned Aerial Vehicles) and in navigation through the development of autonomous driving vehicles. It is more than obvious that sensor systems using only GNSS technology are not suitable for use in the rapidly changing vehicle environment. In a specific task, we were interested in the situations in which position determination problems occur and how many different systems are required to determine a position with reasonable quality. We performed two methods of position determination in the Ljubljana area, Real-Time Kinematic (RTK) and Post-Processing Kinematic (PPK), using three Leica receivers from two series, the Leica GS15 and the Leica GS18T. The instruments were placed on the roof of a car and driven along a predefined route with various obstacles (underpasses, tunnels, forests, tall buildings, etc.). The observations were processed using the commercial software Leica Inifinity and the open-source software RTKlib. The results were analyzed and it was found that it cannot be said that using different instruments under the same conditions will give the same results. The same is true for the comparison between the surveying methods. During the study, we found that the observations post-processed with the Leica Inifinity software package matched the positions determined by the RTK survey method much better than the positions determined with the RTKlib software package. The present study could be continued in the future by evaluating the quality of measurements with integrated GNSS/INS sensors, which allow positioning even when GNSS signals are lost.
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