# Evaluation of Low-Cost GNSS Receiver under Demanding Conditions in RTK Network Mode
## 3 Results
### Forest and Mountain-Like Conditions  
The subsequent measurement stations were located in even more demanding conditions. Point Pt 5 was planned with the horizon obscured from the west (by trees and a nearby football stadium). Additionally, the tripod was set up directly under the tree branches. This was expected to degrade the accuracy of the position measurement significantly. The Pt 6 station, on the other hand, was located in the surroundings of less dense trees, however, on all sides. Additionally, on the southern side the horizon was limited by a nearby mound (sledge hill) and on the western side by the football stadium, as mentioned earlier. The results for each station are presented below (Tables 6 and 7).  
Below (Figure 10) the cumulative graphs for the Pt 5 station are presented, where a significant deterioration in accuracy can be noticed. Because of the horizon obscuration from the west, the biggest differences in relation to the reference coordinates are again visible on the Y axis. It is worth noting that one of the measurements with the u-blox ZED-F9P + ANN-MB-00 set had a float type solution. The results presented here represent the other 4 measurements with a fixed type solution. Therefore, once again it can be seen that the difference of antennas is in favor of a professional GNSS antenna. Nevertheless, in the tested conditions all hardware configurations performed similarly, with an accuracy of \(\pm\)3 cm. The smallest differences from the reference coordinates were achieved by the u-blox ZED-F9P + Leica AS10 set, while the highest measurement repeatability and the lowest standard deviation was achieved by the Leica GS18T.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Receiver** & & **Coordinate** & **Ref. Difference** & **St. Deviation** \\ \hline \multirow{3}{*}{GS18T} & X [m] & 5,548,077.613 & 0.018 & 0.005 \\  & Y [m] & 7,422,240.049 & \(-\)0.024 & 0.015 \\  & H [m] & 204.005 & 0.031 & 0.020 \\ \hline \multirow{3}{*}{ZED-F9P + AS10} & X [m] & 5,548,077.616 & 0.015 & 0.018 \\  & Y [m] & 7,422,240.051 & \(-\)0.026 & 0.009 \\  & H [m] & 204.028 & 0.009 & 0.032 \\ \hline \multirow{3}{*}{ZED-F9P + ANN-MB-00} & X [m] & 5,548,077.618 & 0.013 & 0.011 \\  & Y [m] & 7,422,240.051 & \(-\)0.026 & 0.017 \\ \cline{1-1}  & H [m] & 204.002 & 0.035 & 0.042 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Measurement results on Pt 5.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Receiver** & & **Coordinate** & **Ref. Difference** & **St. Deviation** \\ \hline \multirow{3}{*}{GS18T} & X [m] & 5,548,031.736 & 0.004 & 0.021 \\  & Y [m] & 7,422,213.194 & \(-\)0.008 & 0.025 \\  & H [m] & 204.576 & \(-\)0.004 & 0.038 \\ \hline \multirow{3}{*}{ZED-F9P + AS10} & X [m] & 5,548,031.743 & \(-\)0.004 & 0.011 \\  & Y [m] & 7,422,213.195 & \(-\)0.009 & 0.016 \\  & H [m] & 204.582 & \(-\)0.010 & 0.031 \\ \hline \multirow{3}{*}{ZED-F9P + ANN-MB-00} & X [m] & 5,548,031.742 & \(-\)0.002 & 0.018 \\  & Y [m] & 7,422,213.196 & \(-\)0.010 & 0.022 \\ \cline{1-1}  & H [m] & 204.563 & 0.009 & 0.031 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Measurement results on Pt 6.  
At the Pt 6 station, results on the differences (Figure 11) are surprisingly good, within \(\pm 1\) cm, and therefore similar to the Pt 1 station with a fully exposed horizon. The influence of the environment can only be seen in the bars of standard deviations. The smallest differences from the reference coordinates were obtained by the Leica GS18T receiver, slightly ahead of its rival, while the values of standard deviations definitely favor the u-blox ZED-F9P + Leica AS10 antenna kit.