The u-blox modules are small and inexpensive GNSS receivers that can be used for high-quality positioning. However, they are very sensitive to multipath effects from GNSS signals, resulting in lower position accuracy. In the thesis, we analysed this sensitivity using different choke ring antennas that can improve the ability of the receivers to remove the multipath effect. During the first observations in November 2021 on the roof of the Faculty of Civil and Geodetic Engineering, University of Ljubljana, we studied only the effect of multipath on the u-blox module with or without antenna choke ring. In the second from March 2022, simultaneous observations we used the u-blox module with Leica and Javad choke ring antennas, but this time we also used the Ardusimple receiver and the Leica GS18T receiver for better comparison of multipath effects. The Leica choke ring antenna can only remove multipath from GPS signals, while the Javad choke ring antenna can remove multipath from GPS, GLONASS, Galileo and BeiDou signals. During the observations, we compared RMS values representing the magnitude of the multipath effect. The values were compared for different frequencies (L1, L2 and E5b) and satellite systems (GPS, GLONASS, Galileo and all satellite systems combined). The results show that the multipath effect affects the u-blox module with any choke ring antenna type more than the Leica GS18T receiver. The multipath effect affects the Ardusimple antenna more than the u-blox module with Leica choke ring, and it is the opposite for Javad choke ring.
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