# Galileo Single Point Positioning Assessment Including FOC Satellites in Eccentric Orbits
## 3 Results
Figure 9: Percentage of Galileo constellation achieved positioning solutions in the YEL2 location excluding (blue bars) and including (red bars) the Milena (E14) and Doresa (E18) satellites for the E1, E5a, E5b, and E5 Galileo signal. The analysis was carried out on 1,728,000 epochs. The error represented in the figures was calculated as the difference between the coordinates obtained from the single-point algorithm and those provided by the station monograph considered as the truth. The figures allow a quick comparison between the accuracy of the solution obtained using (red) or not (blue) the Milena (E14) and Doresa (E18) satellites. It clearly emerges that the use of the two satellites degraded the solution accuracy for all frequencies. Figure 12 shows the density histograms of the E1, E5a, E5b, and E5 single-point position coordinates' error in the case of exclusion (blue) or inclusion (red) of the satellites with broadcast ephemeris. Looking at the figure, we can see that all the histograms except those relative to the vertical component of the solution assumed the maximum value around zero. The histograms of the vertical component are wider than those relative to the other components. Comparing each blue histogram with the red one immediately to its right, we notice that each red histogram showed a peak always slightly lower than the corresponding reported in blue. This indicates that the inclusion of the Milena (E14) and Doresa (E18) satellites worsened the accuracy of the solution. What appears from the figure is detailed in Table 2, where the DRMS (Distance Root Mean Squared) and vertical RMS are shown for both scenarios and for all frequencies. The inclusion of satellites always worsened both the horizontal and vertical accuracy. The difference of the horizontal accuracy went from 0.17 m with E5a frequency measurements to 0.74 m with E1 measurements. The same fate was for the vertical accuracy with a deterioration going from 0.68 m for E5a to 1.2 m for E1 measurements. This was not completely expected since both the HDOP and VDOP parameters decreased when these satellites were included in the solution calculation, as shown in Figure 8. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Freq.** & **DRMS Excl.** & **Vert. RMS Excl.** & **DRMS Incl.** & **Vert. RMS Incl.** \\ \hline E1 & 1.21 & 2.74 & 1.95 & 3.97 \\ E5a & 2.21 & 5.80 & 2.38 & 6.48 \\ E5b & 1.91 & 4.66 & 2.45 & 5.77 \\ E5 & 1.85 & 4.82 & 2.38 & 5.71 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: RMS comparison between two scenarios (including or excluding the Milena (E14) and Doresa (E18) satellites) analyzed. Broadcast ephemeris was used. DRMS, Distance Root Mean Squared. Figure 10: Scatter plot of the E1, E5a, E5b, and E5 single-point position error reported in (**a–d**). Blue and red markers represent errors when the solution was obtained by excluding or including the measurements coming from the Milena (E14) and Doresa (E18) satellites, respectively. The solution was achieved by using broadcast ephemeris. Figures 13 and 14 show respectively the scatter plot of single-point position error and the time series of the vertical error, calculated by using precise SP3 ephemeris, for the E1, E5a, E5b, and E5 frequencies. These figures like Figures 10 and 11 allow comparing the the solution accuracy when the Milena (E14) and Doresa (E18) satellites were included (red) or not (blue). Figure 15 shows the density histograms of the E1, E5a, E5b, and E5 single-point position coordinates' error in the case of exclusion (blue) or inclusion (red) of the satellites with precise ephemeris. Unlike what is shown in Figure 12, when precise ephemerides were used, the inclusion of satellites did not worsen the accuracy. In fact, in the histograms, there was no decrease in the peak. The vertical error showed (as expected due to lower accuracy of vertical component solution) a larger and lower histogram than those of the other coordinates.