# Rapid Tracking Satellite Servo Control for Three-Axis Satcom-on-the-Move Antenna
## 4 Experiment Analysis
### Experiment Results  
Experiments were conducted using both conventional ADRC and modified ADRC for comparison, with each experiment lasting about 30 min. The azimuth orientation of the SOTM antenna when using conventional ADRC and modified ADRC is illustrated in Figure 8. To clarify the curve details and improve the readability of the graphical information, data spanning a continuous 200-s are selected for plotting. From Figure 8, it can be observed that, compared to conventional ADRC, the fluctuation in the azimuth orientation of the SOTM antenna is smaller with the modified ADRC proposed in this paper, indicating that the modified ADRC enables a more precise azimuth orientation of the SOTM antenna. The pitch orientation of the SOTM antenna when using conventional ADRC and modified ADRC is illustrated in Figure 9. Similarly, to clarify the curve details and improve the readability of the graphical information, data spanning a continuous 200-s are selected for plotting. From Figure 9, it can be observed that, compared to conventional ADRC, the fluctuation in the pitch orientation of the SOTM antenna is smaller with the modified ADRC proposed in this paper, indicating that the modified ADRC enables a more precise pitch orientation of the SOTM antenna. Figure 8: The azimuth angles of SOTM antenna when using conventional ADRC and modified ADRC. Figure 9: The pitch angles of SOTM antenna using conventional ADRC and modified ADRC. Integrating the experiment results from both azimuth and pitch orientation, it can be concluded that, relative to conventional ADRC, the use of the modified ADRC introduced in this paper results in better tracking performance of the SOTM antenna towards the target communication satellite. As shown in Table 2, the statistical characteristics of pointing data for SOTM system throughout the entire experiment are presented. In the table, the units for the maximum, minimum, average and range of both azimuth and pitch angles are degrees, while the variance is dimensionless. From Table 2, it can be seen that compared to conventional ADRC, the modified ADRC introduced in this paper has reduced the fluctuation range of the azimuth angle by 22.97% and the pitch angle by 8.47%. This indicates that using the modified ADRC leads to higher precision in the SOTM antenna towards satellite tracking. Next, the real-time automatic gain control (AGC) level, real-time signal to noise ratio (SNR) and signal quality are integrated to verify the communication performance of the SOTM system during the experiment. The AGC levels of the SOTM antenna when using conventional ADRC and modified ADRC are illustrated in Figure 10. Similarly, to clarify the curve details and improve the readability of the graphical information, data spanning a continuous 200-s are selected for plotting. From Figure 10, it can be observed that, compared to conventional ADRC, the AGC levels are higher with modified ADRC proposed in this paper. This indicates that the communication performance of the SOTM antenna is better with the modified ADRC. The SNR of the SOTM antenna when using conventional ADRC and modified ADRC is illustrated in Figure 11. Similarly, to clarify the curve details and improve the readability \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Conventional ADRC**} & \multicolumn{2}{c}{**Modified ADRC**} \\ \cline{2-5}  & **Azimuth Angle** & **Pitch Angle** & **Azimuth Angle** & **Pitch Angle** \\ \hline Max Value & 141.89 & 43.08 & 141.71 & 43.12 \\ Min Value & 140.98 & 42.44 & 140.97 & 42.53 \\ Mean Value & 141.35 & 42.78 & 141.36 & 42.81 \\ Range & 0.91 & 0.64 & 0.74 & 0.59 \\ Variance & \(3.49\times 10^{-2}\) & \(2.12\times 10^{-2}\) & \(3.12\times 10^{-2}\) & \(2.05\times 10^{-2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Statistical characteristics of antenna pointing throughout the entire experimental process. Figure 10: The real-time AGC of SOTM antenna when using conventional ADRC and modified ADRC.