# Addressing the Potential of L5/E5a Signals for Road ITS Applications in GNSS-Harsh Environments +
## 4 Conclusions  
In this study, the performance capabilities of the raw GNSS measurements on L5/E5a/B2a signals from _Android_ devices is investigated for road ITS applications. Specifically, a representative dataset was created by collecting GNSS raw measurements from two _Android_ smartphones, namely, the Xiaomi Mi 8 and OnePlus Nord 2 5G, under GNSS-harsh environments. The raw GNSS pseudoranges obtained on L1/E1/B1 and L5/E5a/B2a were smoothed using a Hatch-Filter and processed through an EKF filter algorithm for computing the estimated PVT solution. In addition, the Doppler-shift measurements derived from the _Android_ devices \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Trajectories**} & \multicolumn{2}{c}{**Horizontal Position RMS (m)**} & \multicolumn{2}{c}{**Horizontal Velocity RMS (m/s)**} \\  & **L1/E1/B1** & **L5/E5a** & **L1/E1/B1** & **L5/E5a** \\ \hline Sub-Urban & 2.9 & 3.5 & 1.4 & 1.7 \\ Urban & 5.3 & 6.8 & 1.5 & 1.8 \\ Deep-Urban & 6.6 & 7 & 1.6 & 2.0 \\ Total & 4.7 & 5.6 & 1.5 & 1.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Horizontal position and velocity RMS errors of Xiaomi Mi 8 with respect to the reference trajectory. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Trajectories**} & \multicolumn{2}{c}{**Horizontal Position RMS (m)**} & \multicolumn{2}{c}{**Horizontal Velocity RMS (m/s)**} \\  & **L1/E1/B1** & **L5/E5a/B2a** & **L1/E1/B1** & **L5/E5a/B2a** \\ \hline Sub-Urban & 6.0 & 4.7 & 2.5 & 2.0 \\ Urban & 6.2 & 4.8 & 1.8 & 1.5 \\ Deep-Urban & 6.8 & 5.8 & 1.9 & 1.8 \\ Total & 6.2 & 4.9 & 2.1 & 1.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Horizontal position and velocity RMS errors of OnePlus Nord 2 with respect to the reference. were integrated into the EKF filter. The PVT solutions for L1/E1/B1 and L5/E5a/B2a were compared against a reference PPK trajectory produced from high-grade navigation equipment and software. Data analysis revealed that both smartphones used in this study track more satellites on L1/E1/B1 signals than on L5/E5a/B2a. Additionally, a slight improvement in the tracking capabilities has been observed for the most recently released device (i.e., OnePlus Nord 2 5G) for the L5/E5a/B2a signals compared to Xiaomi Mi 8. Furthermore, data collection on the L1/E1/B1 seems to exhibit higher C/N0 values, compared to those for L5/E5a/B2a; however, abrupt changes occur more frequently irrespective of the satellite's elevation. Contrariwise, measurements on L5/E5a/B2a tend to exhibit lower C/N0 values, but with fewer abrupt changes, which however relate to an increase in the satellite view angle. In terms of multipath, the investigation shows that pseudorange measurements on L5/E5a/B2a signals are more robust than those obtained on L1/E1/B1. Regarding the PVT performance, the results obtained for both devices collecting data on the L5/E5a/B2a signals are promising. In particular, for Xiaomi Mi 8, even though the PVT solution refers to only L5/E5a measurements, it achieves a comparable performance with that of L1/E1/B1, in terms of horizontal position and velocity errors. On the contrary, for the case of L5/E5a/B2a signals, the PVT solution for the OnePlus Nord 2 5G shows a significant improvement when compared to the PVT solution for L1/E1/B1 signals. In order to further improve the PVT solution, it is proposed that future work will focus on the single differences between satellites as the basic functional model. In this approach, it is foreseen that receiver specific biases should be mitigated to a great extent, and therefore, a better performance of the Hatch-Filter should be realized [8]. Also, a range of additional, contemporary smartphones shall be tested, as in the experiment conducted in this paper, a Record and Replay system (Racelogic's LabSat 3 Wideband) was utilized. Conceptualization, A.H., H.P. and V.G. ; methodology, A.H.; software, A.H.; validation, A.H. and V.G. ; formal analysis, A.H.; investigation, A.H., M.O., H.P. and V.G.