# Assessment of GNSS Galileo Contribution to the Modernization of CROPOS's Services
## 3 Results
### Kinematic Observations Using VPPS  
According to the observation schedule designed before the field measurement activities, each kinematic observation session consisted of three series (each series featuring 30 epochs). Before each series, an independent initialization was gained, meaning that the connection to the server was interrupted, subsequently re-established, and a new initialization was carried out, providing independent ambiguity fixed solutions. After three observation series using GPS-GLO-GAL (GGG) satellite systems, an additional three series using GAL-only observations were carried out. Upon the automatic connection to the mount point CROPOS_VRS_GGG_RTCM32, the correction data stream was established and, soon after, the fixed ambiguity solutions were obtained. The survey style regarding the coordinate determination with GAL-only data was slightly modified: the PDOP mask was set to the maximum value of 25 in order to make possible solutions in those circumstances when PDOP value would reach values above the default of 6 (e.g., ninth session with high PDOP values). Each solution was named according to the rule: 'STATION-session #-series number within the session' (e.g., A-1-1). The first three solutions (e.g., A-1-1, A-1-2, A-1-3) were obtained from GPS-GLO-GAL observations, the next three solutions were obtained with GAL-only observations (e.g., A-1-4, A-1-5, A-1-6), etc. In almost all sessions, the VPPS measurements were performed in the time span of 4-6 min (see Table 2), providing very similar observation conditions and satellite visibility and thus enabling the comparison of the results. In that regard, the only exception was session #4, where a 30-min gap occurred between GGG and GAL-only observations owing to some problems with the connection to the base. After the field activities, all created jobs were downloaded from the T7 device to the PC and converted to several ASCII files. Several file formats were combined to obtain the  
Figure 8: All individual static GGGB and ‘GAL-only’ sessions results plotted together: green circle (6 mm) and cyan circle (5 cm) show the maximum departure of ‘GAL-only’ and GGGB from the REFERENCE solution, respectively. following information: Point # ID, Easting, Northing, Hz Precision, Vt Precision, PDOP, number of satellites, and time of observation. A straightforward way to perform the analysis of the results obtained with the VPPS was to compare them with the REFERENCE. The values of the differences displayed in Figure 9 are in the range as follows: \(\Delta\)E GGG (\(-\)4.3 mm to \(+\)5.2 mm) and \(\Delta\)E GAL (\(-\)2.3 mm to 5.8 mm), confirming a slightly higher departure of the GAL solution from the REFERENCE. Interestingly, the RMS and STDEV values are given as follows: RMS \(\Delta\)E (GGG) = 3.0 mm, STDEV \(\Delta\)E (GGG) = 3.0 mm; RMS \(\Delta\)E (GAL-only) = 3.2 mm, STDEV \(\Delta\)E (GAL-only) = 2.9 mm. When the \(\Delta\)N differences are analyzed across all VPPS solutions, the results are given as follows. The values of the differences displayed in Figure 10 are in the range of \(\Delta\)N GGG (\(-\)4.5 mm to \(+\)3.1 mm) and \(\Delta\)N GAL-only (\(-\)6.5 mm to 4.9 mm). The range values (7.6 mm vs. 11.4 mm) along with the extreme value are higher for GAL-only solutions; the RMS (2.2 mm vs. 2.7 mm) and STDEV (2.1 mm vs. 2.6 mm) follow the same pattern, giving slightly higher values for GAL-only results. A similar analysis can be performed for the height component (Figure 11). The extreme values of \(\Delta\)H are given in the range of GGG (\(-\)11.9 mm to \(+\)5.1 mm), GAL (\(-\)14.9 mm to \(+\)6.8 mm). The RMS and STDEV values are given as follows: GGG (RMS = 4.3 mm, STDEV = 3.4 mm), GAL-only (RMS = 6.3 mm, STDEV = 5.2 mm). This is the confirmation that GAL-only solutions have shown a higher deviation from the REFERENCE. That especially came into evidence during the last session (A-9), with six to seven satellites being initially available, and then the visibility dropped below five satellites, preventing the fixed solution.