## 5 Simulation Results
### Effective Coverage Area  
An important parameter that should be taken into account is the effective coverage area. This parameter is extremely important due to developed tasks that are related to the search and localization of human beings in a disaster zone. The idea of swarm drone exploration is supported by the aim to inspect every small space into the disaster zone at least once by at least one drone. The most insignificant failure in the exploration can be translated into the loss of human life, so it is preferable that the same area within the disaster zone be inspected by more than one drone. Generating in this way more robustness to the task of search and localization, this search and rescue approach gives great importance to the use of a drone swarm, which seeks to increase the probability of finding victims. The effective coverage area is defined as a corridor through which the swarm travels. This corridor is as long as the area to explore and the width depends on the number of drones since the width of the area depends on the number of drones that are located across the width of the swarm. The width of the coverage area is directly related to factors such as the number of drones, comfortable distance between drones \((d)\) previously defined in (3), and the radius of sensors coverage \((r)\) used to perform the inspection and search tasks. In order to analyze the exploration degree of the covered zone, several experiments were carried out in which the parameter r was varied in relation to d as shown in Table 2.  
The experiment aim is the percentage calculation of the unexplored and explored area by at least one, two, three, or more drones. Figure 14 shows the simulation of the experiment and the representation of different degrees of exploration for the areas covered by the drone in its trajectory towards the endpoint. The Figure 15 shows different experimental cases where the covered area by the swarm is depicted by several gray color levels through the path to the endpoint. Figure 15 shows how explored area changes according to the relationship between \(r\) and \(d\). In Figure 15 from (a) to (d) is showed the covered area using a swarm of 23 agents. The covered area increases according to \(r\) value approaches to \(d\). Figure 15e,f shows how the explored area is affected by the swarm agent number. The covered area percentage in relation to the values of \(r\) and \(d\) is depicted by Table 2, which describes seven experiments where the rate between \(r\) and \(d\) is studied from \(r=d/15\) to \(r=d\). From Table 2 it is concluded that explored area increase significantly through the increase of the r factor. The equilibrium point is reached when \(r=d/4\) because is in this point, where 100% and 80% of the entire area is explored by at least two drones. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Agents Number** & **Average Convergence Iteration** & **Standard Deviation** & **Average Convergence Time** \\ \hline
3 & 176.6 & 8.3 & 90.6 (mS) \\
5 & 404.9 & 22.4 & 103.9 (mS) \\
7 & 602.6 & 39.4 & 144.5 (mS) \\
10 & 1162.4 & 102.3 & 226.6 (mS) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Convergence data depending on the number of agents. Figure 14: Formation control applied to the 3 agents sub-swarm generated by localization of a victim. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**r** & **Uncovered** & **Covered** & **+2 Drones** & **+3 Drones** & **+4 Drones** & **+5 Drones** \\ \hline d/15 & 43.10\% & 56.89\% & 9.55\% & 0.0014\% & 0.0\% & 0.0\% \\ d/8 & 13.51\% & 86.48\% & 42.01\% & 4.35\% & 0.0069\% & 0.0\% \\ d/5 & 1.73\% & 98.26\% & 73.28\% & 24.57\% & 3.06\% & 0.0\% \\ d/4 & 0.0\% & 100\% & 87.77\% & 54.55\% & 20.53\% & 0.20\% \\ d/3 & 0.0\% & 100\% & 94.34\% & 80.14\% & 52.72\% & 14.56\% \\ d/2 & 0.0\% & 100\% & 98.17\% & 94.04\% & 85.42\% & 71.26\% \\ d & 0.0\% & 100\% & 100\% & 100\% & 97.57\% & 96.11\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Percentage of the covered area according to different rate values between \(r\) and \(d\).