## 4 Discussion  
The possibility of utilizing the GNSS surveys for object navigation and geodetic measurements are dependent on its positioning accuracy, which is strictly related to the number of satellites forming the constellation [42]. In accordance with the literature [43], using two satellite systems (GPS and GLONASS) significantly increases the accuracy of measurements. The results from determining the coordinates of the control points using the static surveys method with a single receiver stated, for all calculation variants, that the error in the position of the point in the horizontal plane (D\({}_{\rm XY}\)) did not exceed 0.03 m and, quite abnormally, was twice as large as the error in determining the point in the vertical plane (D\({}_{\rm Z}\)). In general, the largest differences in coordinates (calculated from reference coordinates) were obtained for the adjustment using only one system (GPS), while the minimum differences in the coordinates were found for the solution using observations from both systems (GPS and GLONASS). In the considered scenarios of the measurements, the biggest difference for the X coordinate equal to 0.160 m was obtained for point 10030 (30 s GL). However, the smallest difference for the X coordinate equal to 0.000 m was obtained for point 10070 (30 s G&GL). The biggest difference for the Y coordinate equal to 0.170 m was obtained for point 10030 (15 s GL). However, the smallest difference for the Y coordinate equal to 0.000 m was obtained for points: 10000 (5 s G&GL), 18970 (5 s GL, 10 s GL, and 15 s GL), 10020 (15 s G&GL, 15 s G), 18966 (15 s G&GL and 30 s G&GL), and 10070 (15 s G&GL). The biggest difference for the height (for Z coordinate), equal to 0.248 m, was also found for point 10030 (30 s GL). On the other hand, the smallest difference for the Z coordinate equal to 0.000 m was obtained for points: 10020 (30 s G&GL) and 10080 (1 s G&GL). The results from determining the coordinates of the control points using the multi-variant survey method stated that the highest number of maximum coordinate differences from the reference coordinates were obtained for the total angular-linear and RTK/RTN measurements assumed on the basis of corrections from the virtual reference stations (VRS corrections). On the other hand, the most measurement results close to the reference coordinates were obtained for the multi-variant surveys with corrections from a single station (SRS). In detail, the biggest difference for the X coordinate equal to \(-0.018\) m was obtained for point 10030 (VRS). However, the smallest difference for the X coordinate equal to 0.002 m was obtained for point 10000 (SRS). The biggest difference for the Y coordinate equal to \(-0.013\) m was obtained for point 10080 (SRS). However, the smallest difference for the Y coordinate equal to 0.000 m was obtained for points: 10020 (SRS), 10030 (MAC and SRS), 10040 (SRS), 18966 (MAC), and 10070 (MAC). The biggest difference for the height (for Z coordinate), equal to \(-0.038\) m, was obtained for point 10080 (VRS). On the other hand, the smallest difference for the Z coordinate equal to \(-0.001\) m was obtained for point 10030 (SRS). In the results from the method establishing control network points by using RTK/RTN surveys, the greatest number of measurement results close to the reference coordinates were obtained for the MAC corrections and for the height for corrections from a single station (SRS). The highest number of maximum coordinate differences was obtained for the control network points established on the basis of corrections from the virtual reference stations (VRS corrections), while the number of minimum coordinate differences was very similar for all types of corrections. In detail, the biggest difference for the X coordinate equal to \(-0.031\) m was obtained for point 10030 (VRS). However, the smallest difference for the X coordinate equal to 0.002 m was obtained for the following points: 18970 (SRS), 18966 (VRS), and 10080 (MAC and VRS).