## 3 Experimental Results
### Comparison of Location Results in Different Scenarios
#### 3.1.4 Headspace Occluded Scene
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Category**} & \multicolumn{5}{c}{**Positioning Results**} \\ \cline{3-8} \multicolumn{2}{c}{} & \multicolumn{2}{c}{**Open Scene**} & \multicolumn{2}{c}{**Semi-Occluded Scene**} & \multicolumn{2}{c}{**Surrounding Occluded Scene**} & \multicolumn{2}{c}{**Headspace Occluded Scene**} \\ \hline \multirow{3}{*}{\begin{tabular}{c} Position error \\ RMS (m) \\ \end{tabular} } & North & 2.1763 & \multirow{3}{*}{mean (m) 2.1057} & 2.5278 & 2.5424 & 2.3332 & \multirow{3}{*}{mean (m) 2.4211} & 2.3475 & 2.3332 & \\  & East & 2.8946 & & 1.4039 & & 2.2325 & & 4.2179 & \\ \hline \multirow{3}{*}{\begin{tabular}{c} Velocity error \\ RMS (m/s) \\ \end{tabular} } & North & 0.4228 & & 0.5425 & & 0.5485 & & 0.6874 & \\  & East & 0.3724 & & 0.3541 & 0.2947 & mean (m/s) 0.3697 & 0.3506 & mean (m/s) 0.4284 & 0.5531 & mean (m/s) 1.0380 \\  & Down & 0.2670 & & 0.2720 & & 0.3862 & & 1.8735 & \\ \hline \multirow{3}{*}{\begin{tabular}{c} Attitude error \\ RMS (deg) \\ \end{tabular} } & North & 1.7171 & & 1.0962 & & 1.6801 & & 22.6026 & \\  & East & 2.1207 & & 1.0798 & mean (deg) 2.2385 & 3.2356 & & 22.6026 & \\  & Down & 2.9790 & & 4.5395 & & 5.0875 & & 41.7349 & \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} GNSS \\ \end{tabular} } & PDOP & 0.7943 & & 0.7919 & & 0.7943 & & 1.1255 & \\  & HDOP & 0.6432 & & 0.6376 & & 0.6432 & & 2.0309 & \\  & VDOP & 1.0798 & & 1.0731 & & 1.0798 & & 4.4642 & \\ \hline \multirow{3}{*}{
\begin{tabular}{c} LEO \\ \end{tabular} } & PDOP & 0.6947 & & 4.0836 & & 1.8337 & & 0.1811 & \\  & HDOP & 0.6319 & & 1.7258 & & 4.0196 & & 0.8646 \\ \cline{1-1}  & VDOP & 0.9153 & & 1.7811 & & 4.5272 & & 1.8796 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Positioning results. Figure 16: DOP value of the Headspace occluded scene. As shown in Table 7, if a sub-filter positioning accuracy is higher than several orders of magnitude than another sub-filter, the information factor ratio of this sub-filter needs to be close to 1. The above conclusion can be seen from the compared simulation results. In this way, the positioning results of federated filter can be significantly improved. It can be seen from Figure 17, since the LEO/INS positioning accuracy is higher than GNSS/INS and 5G/INS, Case3 can improve the overall positioning accuracy by increasing the proportion of the LEO/INS information factor to 80%. At the same time, this paper also compares the federated filtering positioning accuracy of different modes under the same scale factor (using the percentage in Case1), as shown in the figure below. From the comparison of Figures 18-20, it is found that the federated filter under different modes has no obvious difference in position error. However, the FFR mode performs poorly in speed error and attitude angle error, which is reflected in the large error fluctuations, and the attitude angle error reaches 10\({}^{\circ}\) in magnitude. After analysis, it is considered that the filter in this paper adopts the error state vector model, and different modes have different ways to deal with the covariance matrix. The covariance matrix of FFR mode feedback leads to the instability of the sub-filter, which leads to the speed error increasing to the level of 1 m/s after 100 s and the attitude angle error increasing to the level of 10\({}^{\circ}\) after 200 s. FNR mode does not affect the sub-filter, so the positioning result \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Category**} & \multicolumn{3}{c}{**The Percentage (\%)**} \\ \cline{2-4}  & **GNSS** & **LEO** & **5G** \\ \hline Case1 & 33 & 34 & 33 \\ Case2 & 80 & 10 & 10 \\ Case3 & 10 & 80 & 10 \\ Case4 & 10 & 10 & 80 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: GNSS/INS, LEO/INS, and 5G/INS sub-filter information factor ratio. Figure 17: Federated filtering position errors of different information factors. has no influence. The velocity error in FNR mode is less than 0.5 m/s, and the attitude angle error is less than 2.5\({}^{\circ}\).