# Galileo Single Point Positioning Assessment Including FOC Satellites in Eccentric Orbits
## 3 Results  
As reported in the Introduction, Galileo E20 was declared unavailable since 27 May 2014; thus, it was not been considered in the following analysis. Figure 3 shows the evolution of the Carrier-to-Noise density ratio (C/N\({}_{0}\)) of the Milena (E14), Doresa (E18), E1, E2, and E19 (IOV) Galileo satellites with respect to satellite elevation angle for the different frequencies E1, E5a, E5b, and E5 depicted in Panels (a)-(d), respectively, during DOYs 52-71 of 2018. Each panel shows the average of C/N\({}_{0}\) over elevation bins of 10 degrees. In the figure, the E19 satellite was added as representative of IOV satellites. The signals transmitted by the E19 satellite showed a lower level of C/N\({}_{0}\) than those transmitted by the FOC satellites. This occurred because IOV satellites have less transmission power than FOC satellites since 27 May 2014 [1], when a power anomaly on the E20 satellite led the E5 and E6 signals to a permanent loss of power. After this failure, all IOV satellites were backed-off, and thus, their signals have less transmitted power than the FOC satellites. The evolution of the C/N\({}_{0}\) of the E14 and E18 satellites is similar to that of the other FOC satellites in the YEL2 site. As expected, the Milena (E14) and Doresa (E18) satellites showed a higher C/N\({}_{0}\) with respect to the other FOC satellites, confirming results shown by [PERSON] et al. [12]. This behavior is due to lower altitude of Milena (E14) and Doresa (E18) caused by their elliptical orbit. Figure 4 shows the comparison between the carrier-to-noise density ratio (C/N\({}_{0}\)) at the different frequencies of the Milena (E14) and Doresa (E18) satellites. Panel (a) is related to the Milena (E14) satellite, while Panel (b) to Doresa (E18). In both panels, the E1, E5a, E5b, and E5 signals are plotted in blue, red, yellow, and purple, respectively. The E1 signal had a C/N\({}_{0}\) higher than the E5a signal up to 30 degrees. Between 30 degrees and 35 degrees, the two signals showed the same C/N\({}_{0}\), and then, starting from 40 degrees, E5a had a C/N\({}_{0}\) higher than the E1 signal. Results reported in figure confirm the results reported by [PERSON] [10] with the exception of the E1 and the E5a signals at low elevation angles. Figure 5 shows the percentage of epochs with the same satellite number reported on the \(x\) axis. Blue bars refer to the Galileo configuration without the Milena (E14) and Doresa (E18) satellites, while red bars refer to the Galileo constellation including them. The figure shows that, when the Milena (E14) and Doresa (E18) satellites were included, the percentage of epochs with seven or more visible satellites was greater than the percentage one obtains when they were excluded. Consequently, excluding the Milena (E14) and Doresa (E18) satellites, the percentage of epochs with a number of visible satellites less than seven was higher. Particularly, the exclusion of the Milena (E14) and Doresa (E18) satellites increased the percentage of epochs with less than four visible satellites, decreasing the system availability. The system availability is defined as the epoch percentage where the number  
Figure 3: Carrier-to-Noise density ratio (C/N\({}_{0}\)) of the Milena (E14), Doresa (E18), E1, E2, and E19 (IOV) Galileo satellites (depicted in blue, red, yellow, green, and purple dotted lines, respectively) on different frequencies as a function of satellite elevation. The E1, E5a, E5b, and E5 frequencies are reported in (**a–d**), respectively. Each panel shows the average of C/N\({}_{0}\) over elevation bins of 10 degrees. Data plotted refer to DOYs 52–71 of 2018.  
of satellites is greater than four, and it does not indicate the percentage of epochs where a single code position solution can be achieved. This parameter can be considered as an upper bound: the percentage of epochs where the position solution could be achieved is always lower than system availability since the errors that afflict the pseudorange and the goodness of the ephemeris have not been considered.