## 4 Results and Discussion
### Static Test
The RMSE and improvement percentages of the PCP models compared to SPP are detailed in Table 7. As shown in Figure 8, a decrease in positioning accuracy can be observed for HP40 in the horizontal plane of Mi11 in the static complex scenario due to partial obscuration of satellite observations. For Mi11, a similar jump phenomenon occurred in both the static open-sky and complex scenarios, but its amplitude was smaller in the latter case. The decrease in amplitude may have resulted from obstacles hindering weak satellite signals in the complex scenario. Apart from this phenomenon, the other PCP models exhibited similar performance in terms of positioning accuracy. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{2}{*}{**Device**} & \multirow{2}{*}{**Model**} & \multicolumn{4}{c}{**RMSE (m)**} & \multicolumn{4}{c}{**Imp**} \\ \cline{3-8}  & & **E** & **N** & **U** & **E** & **N** & **U** \\ \hline \multirow{4}{*}{HP40} & SPP-P1I & 4.72 & 3.49 & 10.97 & / & / & / \\  & DF-P1I & 0.28 & 0.96 & 1.26 & 94.13\% & 72.52\% & 88.55\% \\  & IFUC1P1I & 0.28 & 0.96 & 1.26 & 94.13\% & 72.52\% & 88.55\% \\  & IFUC12 PII & 0.24 & 1.02 & 1.27 & 95.02\% & 70.68\% & 88.39\% \\  & SPP-P1I & 5.54 & 4.27 & 14.42 & / & / & / \\  & DF-P1I & 2.20 & 1.20 & 1.21 & 60.33\% & 71.94\% & 91.63\% \\  & TF-P1I & 2.08 & 1.52 & 4.66 & 62.42\% & 64.36\% & 67.67\% \\  & IFUC1P1I & 2.08 & 1.56 & 1.52 & 62.44\% & 63.43\% & 89.43\% \\  & IFUC12 PII & 1.80 & 1.09 & 1.23 & 67.50\% & 74.43\% & 91.50\% \\  & IFUC123 PII & 1.55 & 0.79 & 1.21 & 71.92\% & 81.54\% & 91.59\% \\  & SPP-P1C & 5.40 & 4.11 & 14.75 & / & / & / \\  & DF-P1C & 1.73 & 0.99 & 1.97 & 67.97\% & 75.82\% & 86.66\% \\  & TF-P1C & 1.66 & 1.29 & 2.54 & 69.33\% & 68.68\% & 82.77\% \\  & IFUC1P1C & 1.64 & 1.12 & 1.60 & 69.60\% & 72.65\% & 89.15\% \\  & IFUC12P1C & 1.43 & 0.72 & 1.24 & 73.45\% & 82.53\% & 91.59\% \\  & IFUC123P1C & 1.57 & 0.60 & 1.16 & 70.98\% & 85.35\% & 92.17\% \\ \hline \end{tabular}
\end{table} 
Table 7: RMSE results and improvement percentages compared to SPP in the static complex scenario. Figure 7: Positioning accuracy in the static scenario. (**a**) In the static open-sky scenario; (**b**) in the static complex scenario. Table 7 and Figure 7b show that HP40 exhibited better positioning performance in both HP40 and Mi11. Additionally, for Mi11, the positioning performance was slightly better in the IF-P1C and IFUC-P1C models than in the IF-P1I and IFUC-P1I models. The PCP models demonstrated significant improvements over SPP. For HP40, the PCP models achieved sub-meter-level accuracy in the E direction and meter-level accuracy in the N and U directions. These improvements represent an increase of approximately 94%, 71%, and 88% in each direction, respectively, compared to SPP. Similarly, for Mi11, the PCP models achieved approximately two meters of accuracy in the E direction and meter-level accuracy in the N and U directions, except for the TF-P model. Compared to SPP, there was an improvement of about 68%, 75%, and 90% in each direction, respectively. In the static test, it could be observed that increasing the number of frequencies can improve positioning accuracy. The IFUC12 and IFUC123 models exhibited similar positioning performance, indicating that they may have reached the accuracy limit of the PCP models. When comparing different static scenarios, the TF-P model in Mi11 was found to perform the worst among the PCP models. This could be attributed to the quality control method for the TF-P model observations not being rigorous. Additionally, in the complex scenario, the U-direction positioning performance was better than in the open-sky scenario. This improvement could be due to the complex environment blocking some satellite signals  
Figure 8: Position errors in the static complex scenario. (**a**) HP40 positioning errors in the IF-P1I and IFUC-P1I models; (**b**) Mi11 positioning errors in the IF-P1I and IFUC-P1I models; (**c**) Mi11 positioning errors in the IF-P1C and IFUC-P1C models. with weak anti-interference capabilities.