# Improving Human Ground Control Performance in Unmanned Aerial Systems
## 4 The Study
### Results  
Since in our scenario the performance consists of SA, CT and DBH, we formulate the following sub-hypotheses:  
**Sub-Hypothesis 1.1.1:**_In normal conditions, SA is higher in the shared setting compared to the non-shared setting._  
**Sub-Hypothesis 1.2.1:**_In case of unexpected events, SA deteriorates more in the non-shared setting compared to the shared setting._  
**Sub-Hypothesis 1.1.2:**_In normal conditions, DBH is larger in the shared setting compared to the non-shared setting._  
\begin{table}
\begin{tabular}{c} \hline \hline
**\# Question** \\ \hline
**Q1.** How many UAVs are you controlling? \\
**Q2.** What is the altitude and battery level of each of the UAVs? \\
**Q3.** What is the next UAV target on the screen? \\ \hline \hline \end{tabular}
\end{table}
Table 1: Questions asked during the test to assess operator situational awareness.  
Figure 5: Two users operating in the “Shared” setting during the experiment.  
**Sub-Hypothesis 1.2.2:**_In case of unexpected events, DBH deteriorates more in the non-shared setting compared to the shared setting._  
**Sub-Hypothesis 1.1.3:**_In normal conditions, **NQ** is smaller in the shared setting compared to the non-shared setting._  
**Sub-Hypothesis 1.2.3:**_In case of unexpected events, **NQ** increases more in the non-shared setting compared to the shared setting._  
As for SA, users answered three questions while performing the two tasks. The number of correct answers are reported in Table 2 next to the relative \(p\)-value calculated by performing a non-parametric Chi-squared 2-by-2 test. This is to statistically analyze the frequency of correct and incorrect answers for each group. The test shows that there are no significant differences between the correct response frequencies among the two groups, except for Q3 which is related to the operators' prediction factor. Therefore SH1.1.1 is rejected and we can state that there is no significant difference in situational awareness between the two settings when there are no unexpected events. On the other hand, SH1.1.2 is supported by data, so we can affirm that when an unexpected event occurs, the predictive ability of the operators deteriorates, particularly in the \"Non-shared\" setting.  
The Mann-Whitney parametric test analysis was performed. It is adequate to compare two datasets collected from two different groups. The analysis produced a \(p\)-value of 0.271 in the task without an unexpected event and 0.045 in the other case. This indicates that there are no particular differences in the drones returned to base in the first task, rejecting SH1.1.2, while there is statistical evidence in the second case, confirming SH1.2.2.  
Finally, Table 3 shows the number of questions about the mission status asked between the pairs of operators during each task. For each task, the means of the two groups were compared by applying a two tailed independent-samples t-test. For the \"No event\" task, the \(p\)-value is 0.268, thus rejecting hypothesis SH1.1.3. For the second task the \(p\)-value is 0.002 showing that when an unexpected event occurs, the number of questions increases in the \"Non-Shared\" setting.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Correct Answers in** & **Correct Answers in** & \(p\)**-Value** \\  & **Shared Setting Group** & **Non-Shared Setting Group** & \(p\)**-Value** \\ \hline \hline \multicolumn{4}{c}{_No Event task_} \\ \hline Q1 & 20 & 20 & / \\ \hline Q2 & 18 & 16 & 0.376 \\ \hline Q3 & 17 & 13 & 0.144 \\ \hline \multicolumn{4}{c}{_Event task_} \\ \hline Q1 & 19 & 15 & 0.077 \\ \hline Q2 & 18 & 14 & 0.114 \\ \hline Q3 & 18 & 10 & 0.003 \\ \hline \hline \end{tabular} The number of drones that potentially can return home at the end of the mission can vary between 0 and 5. Table 4 shows for each task how many drones each pair of operators managed to bring home.  
\end{table}
Table 2: Number of correct answers per question as measured with SAGAT for each setting.