## 3 Experimental Evaluation
### Kinematic PPP  
The kinematic solutions of all stations are shown in Figure 8, where K represents the results for kinematic PPP. Unlike the static solutions in Figure 5, the Y-axis in Figure 8 is expanded to \(\pm\)2 m for a clearer view. Similar to static solutions, the kinematic positioning errors in the vertical component are larger than those of the horizontal component. However, the kinematic positioning errors are obviously larger when compared with the static solutions.  
Similar to the evaluation method of static PPP, the positioning error within one hour after positioning is taken as the result of convergence, and the RMS of the PPP error after convergence is counted. The kinematic positioning results of BDS-3 (B1 cB2a) are shown in Figure 9.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & **S-C12** & **S-C13** & **S-G** & **S-G+C12** & **S-G+C13** \\ \hline \multirow{4}{*}{**RMS (mm)**} & North & 6.9 & 6.3 & 4.0 & 4.9 & 4.6 \\  & East & 4.7 & 7.0 & 5.6 & 3.6 & 4.8 \\  & Upward & 26.6 & 15.1 & 8.1 & 12.1 & 9.4 \\  & Horizontal & 8.3 & 9.4 & 6.9 & 6.1 & 6.6 \\  & 3-D & 27.9 & 17.8 & 10.6 & 13.5 & 11.5 \\ \hline \multirow{2}{*}{**AVG (mm)**} & North & 2.1 & 1.2 & 0.9 & 1.5 & 1.0 \\  & East & \(-\)0.2 & \(-\)0.7 & \(-\)2.2 & \(-\)0.9 & \(-\)1.2 \\ \multirow{2}{*}{**(mm)**} & Upward & \(-\)23.2 & 2.0 & 2.5 & \(-\)8.6 & 0.7 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Static PPP positioning accuracy and average RMS value statistics.  
It can be seen from Figure 9 that the RMS values of the BDS-3 (B1 cB2a) kinematic PPP results in the three directions of N, E, and U are 2.6, 6.0, and 8.5 cm, respectively. When the horizontal error is converged, the positioning accuracy reaches 6.5 cm, which proves that kinematic PPP can reach centimeter-level positioning accuracy.  
To better compare the results of BDS-3 (B1 cB2a) kinematic PPP, the RMS of kinematic PPP are calculated for BDS-3 (B1 cB2a), GPS, BDS-2+3 (B1 IB3I), GPS + BDS-3 (B1 cB2a), and GPS + BDS-2+3 (B1 IB3I) in the N, E, U, and horizontal directions, and in 3D, as shown in Figure 10.  
Figure 8: Kinematic PPP error series for 20 days at 17 stations utilizing GBM’s precise orbit/clock corrections (the result after the abnormal data are raised).  
Figure 9: Kinematic BDS-3 (B1 cB2a) PPP positioning RMS.  
Figure 10 shows that compared with BDS-2+3 (B1 IB3I), kinematic PPP of BDS-3 (B1 cB2a) reduces the positioning errors of N, E, U, and 3-D error by 29%, 36%, 12%, and 24%, respectively. It can be seen that the observation value of B1 cB2a is more accurate. The kinematic PPP accuracy of BDS-3 (B1 cB2a) is slightly lower than that of GPS. The reason is that the satellite orbits and clock products provided by GBM do not include all BDS satellites, resulting in a relatively small number of satellites that can be used in positioning. On the other hand, the accuracy of the BDS orbit and clock is worse than that of GPS. Different from the impact of static PPP, the number of satellites has a larger impact on kinematic PPP. For the dual-system combination, due to the increase in the number of satellites, the 3-D error is increased by 59% and 70%, respectively, relative to BDS-3 (B1 cB2a) and BDS-2+3 (B1 IB3I). The effect of multi-GNSS on improving the positioning accuracy is more obvious in kinematic positioning. Considering that the receiver coordinates are estimated as white noise, the receiver coordinate parameters cannot be constrained by the explicit kinematics model as in the static processing mode. Therefore, increasing redundant observations can increase the reliability of kinematic solutions [9].