# Study on the Deployment of Ultra-Wideband Positioning Base Stations in Pig Farms
## 4 Experimental Analyses
### Simulation and Analysis  
(1) Different heights of base stations  
A comparative analysis is conducted to examine the impact of varying base station heights on positioning accuracy while maintaining fixed base station spacing and deployment shape conditions. The layout of the base stations is illustrated in Figure 1, wherein A\({}_{0}\) to A\({}_{3}\) represent the respective coordinate positions of each base station. The base stations are set at heights of 0 cm, 75 cm, 125 cm, 175 cm, 225 cm, and 275 cm, respectively. The HDOP value near the center point location is relatively smaller within the enclosed area of the base stations, as depicted in Figure 2 and supported by statistical data. Conversely, the VDOP and PDOP values tend to be larger in this region. Near the base stations, however, both VDOP and PDOP values are smaller compared to those near the center point location. Outside the closed area surrounded by the base stations, all DOP values increase with distance. Figure 1: Coordinates of base stations when height is different. Figure 2: _Cont._The following can be obtained through Table 1:  
The maximum, minimum, and average DOP values of Scenarios a and b are equal to those of the other scenarios. HDOP exhibits the smallest maximum, minimum, and average values among all DOPs, while VDOP and PDOP demonstrate the largest maximum, minimum, and average values. Conversely, Scenario f exhibits the highest maximum, minimum, and average HDOP values compared to VDOP and PDOP. The differences in maximum HDOP values among scenarios do not exceed 0.3; however, there are greater disparities in maximum VDOP and PDOP values between Scenarios b and c compared to other scenarios. In summary, given a fixed shape and spacing of the base stations' arrangement, appropriate adjustment of the height difference between the base stations and positioning \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**DOF** & **Targets** & **a** & **b** & **c** & **d** & **e** & **f** \\ \hline \multirow{3}{*}{HDOP} & Maximum & 1.55 & 1.47 & 1.47 & 1.51 & 1.60 & 1.72 \\  & Minimum & 1.11 & 1.01 & 1.01 & 1.06 & 1.16 & 1.30 \\  & Average & 1.33 & 1.24 & 1.24 & 1.29 & 1.38 & 1.51 \\  & Maximum & 1.62 & 5.58 & 5.58 & 2.02 & 1.49 & 1.35 \\  & Minimum & 0.94 & 1.00 & 1.00 & 0.97 & 0.91 & 0.79 \\  & Average & 1.28 & 3.29 & 3.29 & 1.49 & 1.20 & 1.07 \\  & Maximum & 2.25 & 5.71 & 5.71 & 2.41 & 2.18 & 2.19 \\ PDOP & Minimum & 1.55 & 1.58 & 1.58 & 1.57 & 1.52 & 1.52 \\  & Average & 1.90 & 3.64 & 3.64 & 1.99 & 1.85 & 1.85 \\ \hline \end{tabular} Note: Scenarios a-f correspond, respectively, to heights ranging from 0 to 275 for fixed base station locations.  
\end{table} 
Table 1: DOP values for simulation experiments with different heights of base stations. Figure 2: Mesh and contour plot of HDOP, VDOP, and PDOP. (Note: In this figure, the mesh plot of DOP, the X and Y coordinates are the location of the base stations; the Z coordinate is the value of the DOP.) point can effectively reduce DOP values. Specifically, increasing the height of the base stations will result in larger HDOP values but smaller VDOP and PDOP values. The optimal height range for the base stations is between 175 cm and 275 cm. (2) Different distances of base station  
A comparative analysis was conducted to examine the impact of varying distances between base stations on positioning accuracy, considering a fixed square deployment pattern with the base station height set at 175 cm. The spacing between base station deployments were as follows: 150 cm, 300 cm, 450 cm, 600 cm, 750 cm, and 900 cm. The layout of the base stations is illustrated in Figure 3, wherein A\({}_{0}\) to A\({}_{3}\) represent the respective coordinate positions of each base station. a, b, c, d, e, f, represent scenarios with the base stations spacing of 150, 300, 450, 600, 750, and 900, respectively.