# Data Collection in Areas without Infrastructure Using LoRa Technology and a Quadrotor
## 5 Validation and Results
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Speed [m/s]** & **Distance [km]** & **Battery Consumption** & **Flight Time [min]** \\ \hline
5 & 2.7 & 40\% & 9 \\
7 & 3.6 & 40\% & 8.5 \\
9 & 4 & 38\% & 6.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Flight performance in data collection. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Speed [m/s]** & \begin{tabular}{c} **Transmission** \\ **Diameter [m]** \\ \end{tabular} & \
\begin{tabular}{c} **Transmission** \\ **Time [s]** \\ \end{tabular} &
\begin{tabular}{c} **Average Time** \\ **Per Package [s]** \\ \end{tabular} \\ \hline
5 & 310 & 62 & 20.66 \\
6 & 410 & 65 & 21.66 \\
7 & 470 & 65 & 21.66 \\
8 & 540 & 71 & 23.66 \\
9 & 590 & 64 & 21.33 \\
10 & 690 & 70 & 23.33 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Data collection with UAV. Figure 6: Data collection statistics with UAV. During the return stage, a flight speed of 12 m/s was considered. This is because data do not have to be collected anymore, and it is the maximum speed at which the UAV can fly in normal flight mode and consumes 29% of battery when traveling a distance of 4 km. This is favorable since, in this way, the battery charge is maintained at approximately 30%  
Figure 8: Signal quality transmission (distance vs SNR). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**LoS [m]** & **Transmission Time [s]** & **dBm** & **SNR** \\ \hline
0 & 23 & \(-69.60\) & 39.35 \\
50 & 23 & \(-74.85\) & 36.95 \\
100 & 22 & \(-81.15\) & 30.9 \\
200 & 23 & \(-85.10\) & 17.65 \\
300 & 29 & \(-89.00\) & 3.5 \\
400 & 28 & \(-93.10\) & 1.25 \\
500 & 44 & \(-100.05\) & \(-19.6\) \\
600 & 35 & \(-103.0\) & \(-32.7\) \\
700 & 31 & \(-105.15\) & \(-38.6\) \\
800 & 38 & \(-105.6\) & \(-41.9\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Signal quality in message transmission test with different distances. Figure 7: Signal quality transmission (distance vs. RSSI). to guarantee the completion of the route and to be able to upload the data to the server using Ethernet communication. The main reason for uploading the data to a server is to graphically visualize the information collected by the monitoring devices and compare the data between the different registers and the multiple buoys. The web application shown in Figure 10 allows us to identify the minimum, maximum, and average values for each of the parameters measured by the sensors and compare them with data recorded previously. In order to compare our results with traditionally used methods, simulations were carried out using Radio Mobile and Google Earth software. In these simulations, two monitoring stations (_B_1 and \(B\)2) were placed at the coordinates 19\({}^{\circ}\)31\({}^{\prime}\)49.52\({}^{\prime\prime}\) N, 96\({}^{\circ}\)16\({}^{\prime}\)31.53\({}^{\prime\prime}\) W and 19\({}^{\circ}\)28\({}^{\prime}\)0.56\({}^{\prime\prime}\) N, 96\({}^{\circ}\)15\({}^{\prime}\)15.74\({}^{\prime\prime}\) W (see Figure 11); both stations are 0.5 m above sea level. The location of the stations was chosen based on the work area obtained experimentally with our UAV-LoRa system (see Figure 11d). Thus, three comparison cases were proposed that consider the technical specifications of the transceivers used in the UAV-LoRa system and a data network topology (star, master/slave). These cases are described below:  
* Case 1: one gateway located at coordinates 9\({}^{\circ}\)28\({}^{\circ}\)53.68\({}^{\prime\prime}\) N, 96\({}^{\circ}\)18\({}^{\prime}\)51.94\({}^{\prime\prime}\) W at 30 m height. * Case 2: one gateway located at coordinates 9\({}^{\circ  
The results in Figure 11 show that when using the same technology and maintaining fixed gateways, an antenna of at least 80 m (case 2) or at least two antennas of 40 m (one inside the sea) will be required to collect data from the stations \(B\)1 and \(B\)2. Compared to our proposal, the simulated cases involve additional costs to install the gateways. Additionally, our system can be moved to different areas more easily.