# Rapid Tracking Satellite Servo Control for Three-Axis Satcom-on-the-Move Antenna
## 4 Experiment Analysis
### Experiment Results
of the graphical information, data spanning a continuous 200-s are selected for plotting. From Figure 11, it can be observed that, compared to conventional ADRC, the SNR values are higher with the modified ADRC proposed in this paper. This indicates that the communication performance of the SOTM antenna is better with the modified ADRC. The signal quality of the SOTM antenna when using conventional ADRC and modified ADRC is illustrated in Figure 12. 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 12, it can be observed that, compared to conventional ADRC, the signal quality values are higher with the modified ADRC proposed in this paper. This indicates that the communication performance of the SOTM antenna is better with the modified ADRC. Figure 11: The real-time SNR of SOTM antenna when using conventional ADRC and modified ADRC. Figure 12: The real-time signal quality of SOTM antenna when using conventional ADRC and modified ADRC. As shown in Table 3, the statistical characteristics of the communication-related data for SOTM system throughout the entire experiment are presented. In the table, the expected unit for SNR is dB, the unit for AGC level is V and the unit for signal quality (represented by SQ in Table 3) is %, the variance for all is dimensionless. As shown in Table 3, throughout the entire experiment, compared to conventional ADRC, the modified ADRC introduced in this paper resulted in enhancements in the AGC level, SNR and signal quality of the SOTM system. At the same time, the variance of these three indicators decreased, indicating that the use of modified ADRC improves the communication performance of the SOTM system and makes the communication more stable. It should be noted that, due to the relatively small range of AGC level, SNR and signal quality in the normal running of SOTM system, there will not be a significant difference in the AGC level, SNR and signal quality between the two control schemes in Table 3.  
Finally, tests were conducted on the communication latency of SOTM system using conventional ADRC and modified ADRC separately to verify the effectiveness of the proposed modified ADRC control scheme. These tests were carried out using the operating system's \"ping\" command, with the target address set as China Telecom's \"114.114.114\". The testing sites are shown in Figure 13.  
During the communication latency testing process, the statistical data for communication latency using conventional ADRC and modified ADRC methods are shown in Table 4, where the unit of communication latency is ms.  
Based on the data in Table 4, it can be observed that during the experimental process, in comparison to conventional ADRC, when the modified ADRC proposed in this paper is utilized, the communication latency of the SOTM system is reduced, with lower latency fluctuations (i.e., smaller variance), implying that employing the modified ADRC can decrease the communication latency of the SOTM system, making communication more stable. Integrating all the experiment results, it can be concluded that compared to conventional ADRC, the use of the modified ADRC introduced in this paper results in better precision in tracking target communication satellites of the SOTM antenna, as well as superior communication performance and stability of the SOTM system. This demonstrates that the scheme proposed in this paper is suitable for application in the development of SOTM systems.