# Addressing the Potential of L5/E5a Signals for Road ITS Applications in GNSS-Harsh Environments +
## 3 Analysis  
### Satellites' Visibility, C/N0 and Multipath  
Figures 3 and 4 illustrate the performance of Xiaomi Mi 8 and OnePlus Nord 2 5G in terms of satellites being tracked and the received C/N0 values at specific frequency bands. For the Xiaomi Mi 8, 12, 9 and 11 satellites were being tracked for the GPS, Galileo and BeiDou systems on the L1, E1 and B1 bands, respectively. Regarding L5 and E5a, six GPS and nine Galileo satellites were tracked. OnePlus Nord 2 5G was able to track 12, 9 and 13 satellites for the GPS, Galileo and BeiDou systems on the L1, B1 and E1 bands, respectively. Finally, regarding L5, E5a and B2a, OnePlus Nord 2 5G was able to track eight GPS, nine Galileo and nine BeiDou satellites. The two smartphones have comparable tracking capabilities on L1/E1/B1, albeit OnePlus Nord 2 5G outperforms Xiaomi Mi 8 on the satellites being tracked on L5 for GPS. Figure 3: Xiaomi Mi 8: (**a**) Skyplot of the observed satellites on L1/E1/B1 (solid marks) and on L5/E5a (empty marks), (**b**) L1/E1/B1 and (**c**) L5/E5a/B2a C/N0 elevation-based (grey: elevation \(\leq\) 15\({}^{\circ}\), blue: elevation \(>\) 15\({}^{\circ}\)) series (modified from _GNSSAnalysisApp_ and _RTKLIB_). Figure 2: (**a**) Roof-top sensor platform of the NTUA (National Technical University of Athens) test vehicle, (**b**) NovAtel® PwrPak7, (**c**) iMAR IMU-FSAS, (**d**) GNSS antenna, (**e**) Xiaomi Mi 8, (**f**) OnePlus Nord2 5G. Data analysis reveals two points regarding the elevation-based C/N0 series obtained for the Xiaomi Mi 8 and OnePlus Nord 2 5G (Figures 3 and 4). Firstly, the C/N0 values of the L1/E1/B1 signals both for the Xiaomi mi 8 and the OnePlus Nord 2 5G seem not to depend on the satellite elevation angle, as opposed for the L5/E5a/B2a signals. As a result, in this study, an elevation-dependent weighting scheme is used for L5/E5a/B2a signals and a C/N0-dependent weighting scheme [10] is implemented for L1/E1/B1 signals. Moreover, one should notice that the C/N0 values for L1/E1/B1 signals are higher than those of L5/E5a/B2a ones. On the other hand, the C/N0 values of L5/E5a/B2a signals seem to be less-susceptible to abrupt changes than those observed for the L1/E1/B1 signals. In this study, in order to assess the multipath effect on L1/E1/B1 and L5/E5a/B2a, we use the closed form expression for the dual-frequency ionosphere corrected CMC (Code-Minus-Carrier) linear combination [7,13]. According to Figure 5, the multipath for Xiaomi Mi 8 ranges between \(-\)5 m and 5 m for L1/E1 signals, while for the L5/E5a signals, it lies in the range of \(-\)2 m to 2 m. This discrepancy supports the hypothesis that L5/E5a signals are more resilient to multipath by design, compared to L1/E1 ones. Also, multipath is seen to affect the GPS and Galileo measurements in the same way, as the multipath-RMS values for L1-E1 and L5-E5a are relatively close. Regarding the different sub-trajectories, it seems that multipath has more or less the same effect on the pseudorange measurements, irrespective of the environment type. Nevertheless, excessive multipath is observed both for the urban and deep-urban sub-trajectories. For OnePlus Nord 2 5G, a lower impact of multipath is noticed for L5/E5a/B2a signals compared to those of L1/E1/B1 signals (Figure 6). In numbers, the RMS values observed due to multipath for the L1, E1 and B1 are 1.43 m, 0.96 m and 0.89 m, respectively, while for L5, E5a and B2a, they equal 0.25 m, 0.22 m and 0.17 m, respectively. Based on these results, one can also infer that E1 and B1 signals are more resilient to multipath than the L1, whilst for the L5, E5a and B2a, a more comparable performance is evident. Similar remarks could be made for the sub-trajectories for the OnePlus Nord 2 5G, as those made for Xiaomi Mi 8.