## 3 Materials and Methods
### Location Algorithm Verification
#### 3.3.1 Accuracy Analysis of Fusion Algorithm
Figure 6 shows the CDP function diagram of the WFA fusion positioning scheme. It can be seen from the figure that the positioning error of the WFA fusion scheme is more concentrated in the range of 0-60 m. From the CDP, 67% of the positioning accuracy is within 46.70 m, and 95% of the positioning accuracy is within 123.69 m.  
The comparison of various indicators shows that the positioning accuracy of the WFA fusion scheme has a certain improvement effect. The positioning accuracy of RMSE and CRLB is better than the results of trilateral measurement positioning and least-squares positioning, where only GDOP does not show a better result. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Programme** & \begin{tabular}{c} **Trilateration** \\ **Algorithm** \\ \end{tabular} & \
\begin{tabular}{c} **Least-Squares** \\ **Algorithm** \\ \end{tabular} &
\begin{tabular}{c} **WFA Fusion** \\ **Location Algorithm** \\ \end{tabular} \\ \hline Mean value (m) & 88.40 & 72.91 & 43.32 \\ RMSE (m) & 53.88 & 43.45 & 45.94 \\ CRLB (m) & - & - & 11.25 \\ GDOP & 1.18 & 1.27 & 1.29 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Positioning accuracy evaluation index. Figure 6: WFA cumulative distribution probability. Analysis of WFB Fusion Positioning Accuracy  
The WFB fusion positioning is a positioning scheme based on non-range centroid positioning fusion. Figure 7 shows the comparison between the WFB fusion scheme vehicle positioning trajectory and the vehicle driving trajectory. There are many large error coordinates in the positioning track. From the positioning result calculated by Formula (21), the positioning accuracy analysis diagram of the WFB fusion method can be obtained, as shown in Figure 8.  
In Figure 8, the accuracy analysis of the average positioning error, the RMSE, and the CRLB lower limit of the WFB fusion positioning scheme is carried out. Compared with the positioning error of centroid positioning, the error distance of the WFB scheme is partially reduced to within 50 m, indicating that the positioning accuracy of the WFB fusion positioning scheme has been significantly improved. The positioning error value of the WFB  
Figure 8: WFB fusion method analysis of the positioning accuracy. Figure 7: WFB fusion method trajectory. fusion positioning is closer to the CRLB lower limit, indicating that the positioning accuracy is better. The quantitative comparison of positioning accuracy is presented in Table 7.  
From the comparison of the accuracy evaluation indicators in Table 7, the positioning accuracies of the two positioning schemes are evaluated and compared from the four aspects of error distance average, RMSE, CRLB, and GDOP. From the positioning results, the improvement of the WFB fusion positioning scheme is more obvious. The mean RMSE of the fusion positioning error is 48.56 m. Compared with the 189.65 m of the centroid algorithm, the average positioning error is reduced by 74.39%. The RMSE of the WFB fusion positioning is 45.87 m, which has a 48.52% improvement over the 89.10 m of the centroid algorithm. In terms of GDOP, the GDOP of fusion positioning is 2.62, which is 37.17% worse than the result of single positioning. Figure 9 is the CDP function diagram of the WFB fusion positioning scheme. It can be seen from the figure that the positioning error of the WFB fusion scheme is 0-70 m and that it is relatively concentrated in this range. From the CDP, 67% of the positioning accuracy is within 57.08 m, and 95% of the positioning accuracy is within 127.55 m.  
Comprehensive consideration of the WFB fusion scheme has a significant improvement effect on positioning accuracy. The positioning accuracy of fusion positioning is significantly improved compared to the positioning accuracy of single positioning from the mean error, CRLB, and GDOP, but a large positioning error in the results of the WFB fusion algorithm scheme still exists. 3.