## 4 Results and Discussion
### Case D--Area with Vegetation by the Roadside
Interestingly, the Xiaomi Mi8 smartphone performed well in situations with a threshold of less than 1 m, but in all the situations, the u-bloxes were superior to the Xiaomi Mi 8. The ZED -F9P and Xiaomi Mi8 only achieved positioning quality below 10 cm in a few situations; in this case, the ZED-F9R was slightly better, but it was definitely not comparable to the highly successful Septentrio AsteRx-U. Figure 15: Case D: performance of: (**a**) Septentrio AsteRx-U, (**b**) Xiaomi Mi8, (**c**) u-blox ZED-F9P, and (**d**) u-blox ZED-F9R. \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & \multicolumn{4}{c}{**Type of GNSS Device**} \\ \hline \hline \multirow{2}{*}{**Parameters**} & **Sepentratio** & **u-blox** & **u-blox** & **Smartphone** \\  & **AsteRx-U** & **ZED-F9P** & **ZED-F9R** & **Xiaomi Mi8** \\ \hline GPS solutions & 963 (95.3\%) & 875 (86.5\%) & 860 (85.0\%) & 914 (90.4\%) \\ Fixed ambiguities & 669 (69.5\%) & 46 (5.3\%) & 261 (30.4\%) & 1 (0.1\%) \\ \hline \(dev\_d2p\) \(<\) 1 m & 943 (94.3\%) & 871 (87.1\%) & 849 (84.9\%) & 786 (78.6\%) \\ \(dev\_d2p\) \(<\) 30 cm & 911 (91.1\%) & 167 (16.7\%) & 358 (35.8\%) & 176 (17.6\%) \\ \(dev\_d2p\) \(<\) 10 cm & 793 (79.3\%) & 40 (4.0\%) & 141 (14.1\%) & 11 (1.1\%) \\ \hline \(dev\_d3p\) \(<\) 1 m & 895 (89.5\%) & 783 (78.3\%) & 788 (78.8\%) & 492 (49.2\%) \\ \(dev\_d3p\) \(<\) 30 cm & 895 (89.5\%) & 167 (16.7\%) & 358 (35.8\%) & 176 (17.6\%) \\ \(dev\_d3p\) \(<\) 10 cm & 793 (79.3\%) & 40 (4.0\%) & 141 (14.1\%) & 11 (1.1\%) \\ \hline \end{tabular}
\end{table} 
Table 13: GPS solutions, solutions with fixed ambiguities, and deviation of distances below the given threshold. Situation Case D—open sky conditions with vegetation by the roadside (no. of total: 1001). Figure 16: Percentage of solutions for Case D for (**a**) GPS solutions; (**b**) GNSS solutions. Each bar in a group shows: available solutions (1 st bar), percentage of fixed solutions (2 nd bar), deviation at horizontal distances (3 rd bar, where light blue is for thresholds less than 10 cm, green is for thresholds less than 30 cm, and brown is for thresholds less than 1 m), and 4 th bar shows deviation at spatial distances (yellow, green, and dark red for 10 cm, 30 cm, and 1 m thresholds, respectively). \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & \multicolumn{4}{c}{**Type of GNSS Device**} \\ \hline \hline \multirow{2}{*}{**Parameters**} & **Sepentratio** & **u-blox** & **u-blox** & **Smartphone** \\  & **AsteRx-U** & **ZED-F9P** & **ZED-F9R** & **Xiaomi Mi8** \\ \hline GNSS solutions & 990 (98.0\%) & 971 (96.1\%) & 946 (93.6\%) & 989 (97.9\%) \\ Fixed ambiguities & 711 (71.8\%) & 648 (66.7\%) & 750 (79.3\%) & 8 (0.8\%) \\ \hline \(dev\_d2p\) \(<\) 1 m & 972 (97.2\%) & 970 (97.0\%) & 945 (94.5\%) & 644 (64.4\%) \\ \(dev\_d2p\) \(<\) 30 cm & 967 (96.7\%) & 288 (28.8\%) & 348 (34.8\%) & 141 (14.1\%) \\ \(dev\_d2p\) \(<\) 10 cm & 919 (91.9\%) & 45 (4.5\%) & 115 (11.5\%) & 11 (1.1\%) \\ \hline \(dev\_d3p\) \(<\) 1 m & 972 (97.2\%) & 951 (95.1\%) & 945 (94.5\%) & 577 (57.7\%) \\ \(dev\_d3p\) \(<\) 30 cm & 967 (96.7\%) & 288 (28.8\%) & 348 (34.8\%) & 141 (14.1\%) \\ \(dev\_d3p\) \(<\) 10 cm & 919 (91.9\%) & 45 (4.5\%) & 115 (11.5\%) & 11 (1.1\%) \\ \hline \end{tabular}
\end{table} 
Table 14: GNSS solutions, solutions with fixed ambiguities, and deviation of distances below the given threshold. Situation Case D—open sky conditions with vegetation by the roadside (no. of total: 1001).