## 4 Discussion and Applications  
The paper shows that despite the incomplete operability of the Galileo system, accurate, real-time geodetic measurements can be made using only Galileo satellites signals. The disadvantage of the system is availability of solutions in specific time windows. For the needs of this research, experimental test measurements were successfully performed at a static control point within 6 days at the end of 2017 and beginning of 2018. Three basic problems were examined in this paper, important from the point of view of a surveyor performing geodetic measurements for cadastral works or engineering geodesy tasks. The first one, covering the availability and continuity of positioning. The second one concerning the convergence time needed to achieve the measurement error not bigger than 0.05 m. The third \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Statistics**} & \multicolumn{3}{c}{**A**} & \multicolumn{3}{c}{**B**} \\ \cline{2-7}  & \(\pm m_{\Delta x}\) & \(\pm m_{\Delta y}\) & \(\pm m_{\Delta h}\) & \(\pm m_{\
u_{x}}\) & \(\pm m_{\
u_{y}}\) & \(\pm m_{\
u_{x}}\) \\ \cline{2-7}  & **[m]** & **[m]** & **[m]** & **[m]** & **[m]** & **[m]** \\ \hline _mitu_ & 0.0051 & 0.0173 & 0.0092 & 0.0048 & 0.0042 & 0.0065 \\ _max_ & 0.0728 & 0.0847 & 0.0815 & 0.0660 & 0.0440 & 0.0774 \\ _AV_ & 0.0151 & 0.0291 & 0.0294 & 0.0137 & 0.0094 & 0.0225 \\ _SD_ & 0.0150 & 0.0106 & 0.0152 & 0.0137 & 0.0071 & 0.0142 \\ \(V\) & 99.3\% & 36.5\% & 51.7\% & 100.1\% & 75.4\% & 62.9\% \\ \hline \hline \end{tabular}
\end{table} 
Table 12: List of basic measurement statistics, respectively: A—without taking into account the reduction of absolute errors, B—after taking into account the reduction of absolute errors respectively. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**No of Series \(j\)**} & \multicolumn{3}{c}{**A**} & \multicolumn{3}{c}{**B**} & \multirow{2}{*}{**Number of Measurements**} \\ \cline{2-7}  & \(\pm m_{\Delta x}\) & \(\pm m_{\Delta y}\) & \(\pm m_{\Delta h}\) & \(\pm m_{\
u_{x}}\) & \(\pm m_{\
u_{y}}\) & \(\pm m_{\
u_{y}}\) & **Measurements** \\  
one regarding accuracy of the point determination. As a measure of accuracy, the average error of determining a single point using the RTK was adopted. A three-stage study has shown that the current constellation, 14 fully operational satellites, provides in Krakow (Polska) in some selected periods of the day the possibility of performing precise RTK measurements using signals from Galileo satellites only. The first stage of research on the availability of RTK measurements was as follows (Tables 1-7):  
1. 362 DOY 2017--there were five observation windows with a total duration of 4 h 30 min
2. - the minimum observation window lasted 20 min,
3. - the maximum observation window lasted 2 h 30 min,
4. - the average length of the observation window was 54 min,
5. 363 DOY 2017--there were three observation windows with a total duration of 7 h 40 min
6. - the minimum observation window lasted 10 min,
7. - the maximum observation window lasted 3 h 50 min,
8. - the average length of the observation window was 2 h 33 min,
9. 364 DOY 2017--there were seven observation windows with a total duration of 10 h 20 min
1. - the minimum observation window lasted 10 min,
2. - the maximum observation window lasted 3 h 50 min,
10. - the average length of the observation window was 1 h 28 min,
11. 365 DOY 2017--there were six observation windows with a total duration of 7 h 30 min
2. - the minimum observation window lasted 30 min,
3. - the maximum observation window lasted 3 h 40 min,
4. - the average length of the observation window was 1 h 15 min,
5. 001 DOY 2018--there were three observation windows with a total duration of 7 h 10 min
6. - the minimum observation window lasted 30 min,
7. - the maximum observation window lasted 3 h 30 min,
8. - the average length of the observation window was 2 h 23 min,
9. 002 DOY 2018--there were ten observation windows with a total duration of 11 h 50 min
10.