## 3 Study Results
### Kinematic PPP Positioning Accuracy Using Dual-Frequency Observations  
The study of kinematic PPP accuracy using dual-frequency observations is crucial for robot localization systems as it provides a low-cost solution compared with the high-cost solution using dual-frequency observations [30]. The results of this study show that kinematic PPP positioning accuracy is computed relative to the reference differential solution. Figure 5a presents kinematic PPP coordinate differences using GPS single-frequency observations. Figure 5b presents kinematic PPP coordinate differences using GLONASS single-frequency observations. Figure 5c presents kinematic PPP coordinate differences using mixed GPS/GLONASS single-frequency observations.  
### Kinematic PPP Positioning Accuracy Using Dual-Frequency Observations  
The study of kinematic PPP accuracy using dual-frequency observations is crucial for robot localization systems as it provides the ideal solution compared with the less accurate solution using single-frequency observations. Dual-frequency observations mitigate efficiently the Ionospheric delay (the largest source of errors for GNSS observations) compared with single-frequency observations. Figure 5d presents kinematic PPP coordinate differences using GPS dual-frequency observations. Figure 5e presents kinematic PPP coordinate differences using GLONASS dual-frequency observations. Figure 5f presents kinematic PPP coordinate differences using mixed GPS/GLONASS dual-frequency observations.  
As a result of this study, kinematic PPP positioning accuracy is computed by comparing kinematic PPP observation with the reference differential solution.  
Figure 6a presents kinematic PPP RMSE using single-frequency observations from GPS, GLONASS, and mixed GPS/GLONASS.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**PP Processing Parameters** & **Values** \\ \hline Reference System & ITRF2008 \\ Coordinate format & ENH (UTM) \\  & CODE final \\ Satellite orbit and clock ephemeris source & 30 s for clock \\  & 15 min for orbits \\ Satellite phase center offset & IGS ANTEX \\ Receiver phase center offset & IGS ANTEX \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \multicolumn{2}{c}{} \\ \end{tabular}
\begin{tabular}{c} \hline \hline
**PPP Processing Parameters** & **Values** \\ \hline Reference System & ITRF2008 \\ Coordinate format & ENH (UTM) \\  & CODE final \\ Satellite orbit and clock ephemeris source & 30 s for clock \\  & 15 min for orbits \\ Satellite phase center offset & IGS ANTEX \\ Receiver phase center offset & IGS ANTEX \\  & IGS ANTEX \\  & Saastamoinen \\ Meteorological model & GPT \\   Mapping function & Global Mapping Function (GMF) \\   Ionospheric model & Final Global Ionospheric Maps (GIM) from IGS \\   Mask angle & 10\({}^{\circ}\) \\   Observation type & Code + Phase \\   System & GPS/GLONASS/BeiDou/Galileo/QZSS/IRNSS \\   Frequency & Single/Dual/Triple \\   Processing mode & Static \\ Estimation method & Kalman Filter \\ \hline \hline \end{tabular}
\end{table}
Table 2: PPP processing parameters used in Net_Diff. service.  
Figure 5: Kinematic PPP coordinate differences using (**a**) GPS single-frequency observations, (**b**) GLONASS single-frequency observations, (**c**) mixed GPS/GLONASS single-frequency observations, (**d**) GPS dual-frequency observations, (**e**) GLONASS dual-frequency observations, and (**f**) mixed GPS/GLONASS dual-frequency observations.  
Figure 6b describes kinematic PPP RMSE using dual-frequency observations from GPS, GLONASS, and mixed GPS/GLONASS.