This paper is concerned with an experiment that was intended to compare the respective accuracies of local GNSS monitoring using observations by GPS and GLONASS satellites at different elevations above the horizon. We used data from continuous daily observation sessions in a local network during 3 months in the “static” mode. An analysis of parameters that characterize the accuracy and efficiency of displacement determinations showed that the combined GPS + GLONASS data processing has the highest accuracy at elevation angles greater than 15°. It is shown that the accuracy of GLONASS observations is not considerably worse than that of GPS. We note that the time-dependent variation of GLONASS observation is large. © 2017, Pleiades Publishing, Ltd.