## 3 Results
### Differences between Galileo Solutions  
The impact of using various PCCs can be estimated initially based on the difference in the compared PCCs (dPCCs). By studying the distribution of the dPCCs, one can preliminary predict its impact height (azimuthal symmetry of dPCCs) and its horizontal component (azimuthal asymmetry of dPCCs) [36]. Such a pattern in dPCCs was already tested by [24; 37] for the LEIAR25 antennas, and their results were very promising. In our case, azimuthal symmetry occurred for the majority of the antennas in the dPCCs (E05 minus G02). On this basis, one can expect that the impact of using GPS-based corrections instead of Galileo-based ones should be visible mainly in the height (Figure 3). The one exception is the JAV_RINGATN_G3T antenna, which will be discussed later. Figure 2: Coordinate repeatability of the GPS and Galileo solutions for the DD approach. For the horizontal component, we received, in general, consistent results for both GPS- and Galileo-based PCCs. The average difference in the coordinates for both approaches was not significant, and was 1.3 mm (north) and 0.2 mm (east) for DD and 0.6 mm (north) and \(-\)0.2 mm (east) for PPP. Therefore, one can conclude that using GPS-based receiver antenna corrections does not significantly affect the horizontal component. The one exception is the JAV_RINGANT_G3T antenna mounted at the OBE400 DEU and NYA200 NOR stations, for which the bias for the north component is \(-\)9.9 mm and \(-\)9.1 mm for DD and PPP, respectively. This results from the clear asymmetry in the dPCCs (Figure 3). A similar effect was visible in the work of [23] for the AOAD/M_T NONE antenna mounted at the METS00 FIN station, where the high asymmetry in the dPCC impacted mostly the horizontal component effectively. The height differences varied from \(-\)2.2 mm for SAS200 DEU (DD) to \(-\)15.2 mm for BRUX00 BEL (PPP). The discrepancy was quite large, but the correctness of the results was confirmed by a very high consistency between both approaches (Figure 4). The mean agreement of the height differences received from DD and PPP was at the 2 mm level. However, it should also be noted here that in our study, we tried to homogenize the strategy at some critical points (e.g., cut off elevation) to minimize the discrepancies. We also observed a high discrepancy even for antennas of the same type, but we did not notice a latitude dependency here--the discrepancies came directly from the dPCC patterns (Figure 3). If we look at the dPCCs for the LEIAR25.R4 LEIT antennas, we can distinguish three groups (Figure 5). The first one contains antennas calibrated in 2012 (i.e., REYK00 ISL, HOFN00 ISL, NICO0 CYP, and EUSK00 DEU), the second group calibrated in 2015 (i.e., PTBB00 DEU and ISTA00 TUR), and the last group calibrated in 2017 and later. A clear dependence can be observed between the time of calibration and the dPCCs (Figure 5). The highest differences for both approaches were derived from the oldest calibrations. The mean value for both approaches was \(-\)11.9 mm. A slightly smaller difference occurred in the second group (\(-\)8.3 mm), while for the latest calibrations, the mean difference was \(-\)4.3 mm. Moreover, for the other antenna types, the oldest calibrations (before 2015) exhibited higher dPCC values, resulting in greater height differences (e.g., WRLG compared to GELL and GOR2). This may be related to the hardware modernizations of the anechoic chamber carried out in 2016, and as indicated by the University of Bonn, such modernization may affect the calibration parameters of some antenna types ([PERSON], personal communication). Unfortunately, this does not explain fully the differences between the antennas calibrated in 2012 and 2015. It is also possible that the manufacturing time of the antennas could have caused this issue, which opens up a new area of research. However, in our analysis, a higher correlation was noted for calibration time (r = 0.97) than for manufacturing time (r = 0.30). Figure 3: Differences in PCC (dPCC) between the E05 and G02 tables.