# Galileo Single Point Positioning Assessment Including FOC Satellites in Eccentric Orbits
## 3 Results
The inclusion of the Milena (E14) and Doresa (E18) satellites increased the system availability, varying it from 94.1-97.8%. Figure 6 shows the evolution of dilution of precision parameters of the Galileo constellation in the YEL2 location. The blue points represent DOP values occurring when the Milena (E14) and Doresa (E18) satellites were excluded. The red points represent DOP values obtained including the Milena (E14) and Doresa (E18) satellites. The exclusion of the satellites led to an increase of the DOP parameters, as expected. Figure 4: Carrier-to-noise density ratio (C/N\({}_{0}\)) of the Milena (E14) and Doresa (E18) satellites on different frequencies, E1 (blue), E5a (red), E5b (yellow), and E5 (purple), as a function of satellite elevation plotted in (**a**,**b**) respectively. Figure 5: Percentage of epochs with the same satellite number. The height of each bin represents the percentage of epochs with the number of satellites indicated on the xaxis. Blue bars refer to the Galileo configuration without the Milena (E14) and Doresa (E18) satellites, while red bars refer to the Galileo constellation including the Milena (E14) and Doresa (E18) satellites. The very high values of the DOP in Figure 6 must be attributed to the fact that the Galileo constellation is not yet complete. There were, in fact, epochs where the low number of visible satellites and their non-optimal spatial disposition caused these high values. An example is reported in Figure 7.  
However, in order to make a quick analysis, in Figure 8 is reported a comparison of the daily dilution of precision of the Galileo constellation in the YEL2 location excluding (blue bars) and including (red bars) the Milena (E14) and Doresa (E18) satellites. The comparison was made for GDOP, PDOP, HDOP, and VDOP. Figure 8 clearly shows that the inclusion of the two satellites improved all the DOPs, every day, as the red bars are always lower than the blue ones. This was expected, as the more satellites used in the solution, the smaller the DOP values. Figure 6: Time evolution of the dilution of precision parameters of the Galileo constellation in the YEL2 location. The blue points represent DOP values occurring when the Milena (E14) and Doresa (E18) satellites were excluded. The red points represent DOP values obtained including the Milena (E14) and Doresa (E18) satellites. The ticks on the x axis are spaced 86,400 s (equal to one day); in this way, each tick corresponds to a day. Figure 7: Galileo system skylpot in the YEL2 site on DOY 55 from 4:40–5:00 UTC. Regarding the above-mentioned high values of DOP, it can be noted that the the share of DOP values larger than six was 4.92%, and this is the reason why their presence was not evident in the averages values. Figure 9 shows the percentages of achieved positioning solutions for the E1, E5a, E5b, and E5 frequencies excluding (blue bars) and including (red bars) the Milena (E14) and Doresa (E18) satellites. It should be emphasized that we did not use any threshold for the DOP in order to obtain the greatest number of solutions. The figure clearly shows that the use of the two satellites increased the percentage of the solution for all the frequencies. In detail, the inclusion of the Milena (E14) and Doresa (E18) satellites increased by about 5% the number of solutions obtained, regardless of the frequency used. Figures 10 and 11 show respectively the scatter plot of single-point position error and the time series of vertical error, calculated by using broadcast ephemeris, for the E1, E5a, E5b, and E5 frequencies. Figure 8: Daily dilution of precision comparison of the Galileo constellation in the YEL2 location excluding (blue bars) and including (red bars) the Milena (E14) and Doresa (E18) satellites. GDOP (Geometric Dilution Of Precision), PDOP (Position Dilution Of Precision), HDOP (Horizontal Dilution Of Precision), and VDOP (Vertical Dilution Of Precision) are compared in (**a–d**), respectively.