## 5 Conclusions and Limitations  
Wildfires occur frequently every year, and they cause severe loss of life and property. Therefore, firebreak construction in the field is necessary to prevent the spread of wildfires and protect residential and other critical facilities. Large wildfires often stem from activities such as field burning or crop residue burning. These ignition sources tend to spread rapidly, thus emphasizing the importance of early identification of fires and deployment of measures to prevent their escalation into large-scale wildfires. Proactive responses to ignition sources such as field burning contribute not only to wildfire prevention but also to the safeguarding of residential areas and critical infrastructure, thereby enhancing resource efficiency in firefighting efforts. However, the existing methods rely on manual labor using primitive tools such as hooks, which limits their efficiency and rapid-response capabilities. In this paper, we proposed a fire-extinguishing drone to prevent or delay the spread of wildfires in the initial outbreak stages before the deployment of ground firefighting teams. We implemented a fire-extinguishing drone module capable of deploying six fire-extinguishing balls consecutively. Additionally, we demonstrated the effectiveness of  
Figure 8: Actual deployment points and fire defense lines (experimental results of firebreak construction) and firefighting ammunition explosion. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Performance Indicators** & **Target** & **Validation Method** & **Results** \\ \hline \multirow{2}{*}{Drop accuracy} & \multicolumn{2}{c}{Deployment of 12 fire-extinguishing balls along the defense lines} & \multirow{2}{*}{On-site evaluation} & \multirow{2}{*}{80\%} \\  & & (Drone 1: 6 balls/Drone 2: 6 balls) & & \\ \hline Drone balance & \multirow{2}{*}{Stable hovering} & \multirow{2}{*}{On-site evaluation} & \multirow{2}{*}{100\%} \\   during deployment & & & \\ \hline \multirow{2}{*}{Functionality of deployment module} & Activation of six & \multirow{2}{*}{Operational} & \multirow{2}{*}{100\%} \\  & fire-extinguishing balls & & \\ \cline{1-1}  & (1 st line of defense) & & \\ \hline LTE video transmission & Real-time streaming & On-site evaluation & 100\% \\ \hline RTKs & Accuracy of path & On-site evaluation & 90\% \\ \hline GCS & Ground control system & On-site evaluation & 100\% \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Performance results based on performance metrics. Figure 7: The Issues of Firebreak Continuity. controlling multiple drones using a GCS and the accuracy of the precise designated paths generated using RTK technology for wildfire containment. We conducted several experiments to evaluate the deployment accuracy of fire-extinguishing balls. According to the results, the accuracy of deployment was 100% within a 10-m target range, and the deployment accuracy was 80% for heights of 20 meters or less. A firebreak construction field test was conducted to evaluate the accuracy of continuous fire extinguisher deployment, hovering performance during deployment, accuracy of the RTK-designated paths, and GCS performance. The proposed system achieved 100% performance on all indicators, except for the accuracy of the RTK-designated paths. Continuous deployment of fire-extinguishing balls and firebreak construction proved to be effective for securing critical facilities and protecting designated areas. It facilitated early firebreak construction, thereby improving community safety, wildfire prevention, and operational stability during firefighting efforts. We anticipate that by using multiple units of the fire-extinguishing drones developed herein in tandem, the impact of fires can be minimized by mounting a rapid response, including measures to prevent the spread of wildfires and protect residential and other critical facilities. However, a few issues emerged, such as the tendency of the spherical fire-extinguishing balls to roll upon deployment, which changed their initial positions.