## 3 Materials and Methods
### Location Algorithm Verification  
#### 3.3.1 Accuracy Analysis of Fusion Algorithm  
The performance of wireless positioning methods can be evaluated from many aspects such as positioning accuracy, anchor node density, and energy consumption cost. Among them, the evaluation of positioning accuracy is the most critical. Common positioning accuracy evaluation methods include Cramer Rao lower bound (CRLB), geometric differentiation of precision (GDOP), root mean square error (RMSE), and cumulative distribution probability (CDP), among others. According to the positioning results of the three schemes, the positioning accuracy of the three schemes is compared, and the influence of the selection of the positioning scheme on the positioning effect is analyzed. 1. Analysis of WFA Fusion Positioning Accuracy  
The WFA fusion positioning is a positioning scheme based on range trilateral positioning and least-squares positioning fusion. Figure 4 shows the comparison between the WFA fusion scheme vehicle positioning trajectory and the vehicle driving trajectory. Figure 3: Vehicle trajectory. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Number** & **Data Name** & **Data Sample** \\ \hline
1 & ID & 2 \\
2 & Time & 7:41:07 \\
3 & Time-s & 0.59375 \\
4 & RSSI & 9 \\
5 & Base station IP & 2 \\
6 & GPS-s & 0.359375 \\
7 & Speed & 12.42 (1 knot = 1.852 k) \\
8 & Angle & 94.58 \\
9 & Actual veh GPS & (65573.45175, 5279031.715) \\
10 & Base station GPS & (65705.26914, 5278991.382) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Integration of data fields. There is a continuous large error in the middle of the positioning trajectory, and only some vehicles' trajectory results are suitable. From the positioning result calculated by Formula (20), the positioning accuracy analysis diagram of the WFA fusion method can be obtained, as shown in Figure 5.  
In Figure 5, the WFA fusion positioning scheme analyzes the accuracy of the mean positioning error, RMSE, and CRLB. The positioning error of the WFA scheme is basically controlled within 100 m. Firstly, compared with the three RMSE values, the RMSE of WFA is better than the RMSE of trilateral positioning, which is close to the least-squares result, and the accuracy is improved. Secondly, among the three positioning methods, the positioning error of WFA fusion positioning is the closest to CRLB. From the perspective of CRLB, the positioning accuracy of the fusion scheme is relatively good. The reason why the error distance of individual points is lower than CRLB is that it is assumed that the error in CRLB estimation follows Gaussian distribution, and the error in the experiment is  
Figure 4: WFA fusion method trajectory. Figure 5: WFA fusion method analysis of the positioning accuracy. biased to a certain extent, so some individual errors may exceed the lower limit of CRLB. The quantitative comparison of positioning accuracy is shown in Table 6.  
From the comparison of the accuracy evaluation indicators in Table 6, the positioning accuracies of the three positioning schemes are evaluated and compared from the four aspects of error distance average, RMSE, CRLB, and GDOP. The results show that the WFA fusion algorithm is better than the least-squares method and the trilateral localization algorithm. In terms of mean error, the mean error of WFA fusion positioning is 43.32 m, which is significantly improved compared with 88.40 m for trilateral positioning and 72.91 m for least-squares positioning, and the average positioning error is reduced by 51.00% and 40.58%, respectively. In terms of RMSE, the RMSE of the WFA fusion location is 45.94 m, which is 14.74% higher than 53.88 m for the trilateral location. Compared with 43.45 m of least-squares positioning, the positioning accuracy is improved by 5.73%. In terms of the GDOP, the GDOP of trilateral positioning is 1.18, which is better than the other two positioning methods. The result of 1.29 for the WFA fusion positioning is similar to that of 1.27 for least-squares positioning.