# HelpResponder--System for the Security of First Responder Interventions
## 5 Results
### Test Site 1: Alcorcon USC Fire Tower  
First of all, we describe the space of the evaluation. In Figure 8, there is a map with the confined spaces' dimension for the evaluation and the beacon's network location (B1\(\rightarrow\)B4). It is the basement of the USC. Secondly, to carry out this first test, a cold smoke-generating machine is required to reduce visibility and worsen environmental conditions to test the communication between the beacons. Table 1 shows the RSSI measurement results among peripheral nodes and the central node. The power configured in the network for each of the distances is indicated. Figure 8: The confined space for the evaluation with the support of the USC-Alcorçón. The description of the evaluation is next. After the intervention of the MGAV, the firefighter team could start the interventions (see Figure 9). The firefighters moved along the enclosure perimeter according to emergency intervention procedures and the focus fire detection results. The location of the beacons and the points are deployed, taking into account the coordinates that could guide firefighters in a future development using the interface for the ACP. Additionally, our system offered environmental data, a map, and a recommendation path to navigate the enclosure perimeter in previous firefighters' intervention. With this evaluation, the ACP could optimize a firefighter route with information about the fire focus's location and environmental conditions (moderate temperature and toxicity in the air). This route showed the point of fire focus and the points to explore the environment to find victims. In all cases, RSSI is worse in cold smoke, between 1 and 5 dB on average. It is interesting to program the beacons at their lower transmission power when used in emergencies with adverse environmental parameters [40], such as smoke, to minimize signal strength losses. The theoretical values of RSSI are calculated from [41]. Taking \(n=2\) for free space [42] and varying \(A\), the error between the theoretical and the experimental calculation is close to 1%. The data can be extrapolated from these measurements, adjusting regression curves to obtain the maximum distance between nodes according to the minimum RSSI supported by the beacons, which is \(-96\) dBm. Firstly, comparing the RSSI signal for the same power with and without smoke, one can expect that the smoke case would make the signal worse, but this is not always the case. The peripheral node antenna faces better, with the antenna of the central node improving the RSSI signal. Each one is at a different distance from the central node, so they have different RSSI values. They are all configured to work below \(-92\) dBm in absolute value. When they reach 92 dB in absolute value, they switch off because they cannot operate with such low RSSI quality. That is why we have set the transmit power to the maximum allowed by the manufacturer: 8 dB. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Static Parameters**} & \multicolumn{4}{c}{**Tx = 8 dB**} & \multicolumn{4}{c}{**Tx = 0 dB**} & \multicolumn{4}{c}{**Tx = \(-\) 8 dB**} \\ \cline{3-13}  & & \multicolumn{4}{c}{**RSSI (dBm)**} & \multicolumn{4}{c}{**RSSI (dBm)**} & \multicolumn{4}{c}{**RSSI (dBm)**} \\ \cline{3-13}  & & **B1** & **B2** & **B3**  
Secondly, it will explain the process to obtain the fire's location and orientation once detected. In Figure 10, the used point of the space to deploy the beacons has been represented. Hence, this determines the positions in which the beacons were deployed (B1, B2, B3, and B4). The purple dots and yellow lines show the ideal path to follow to navigate the space. It showed the followed path (red line) of the MGAV to explore the indoor environment and locate the fire's focus. Several points were chosen to emulate the movement of the MGAV (P1, P2, P3, P4, P5, and P6)--see Table 2 according to the received information during the intervention. The actual path is the red line that joins the points P1 to P6.