# Data Collection in Areas without Infrastructure Using LoRa Technology and a Quadrotor
## 5 Validation and Results  
The verification of the transmission range of the transceivers was carried out through tests that consisted of sending a packet with data from the sensors installed in the monitoring stations to receive them with the UAV. These tests were carried out while maintaining a height of 30 m and a constant flight speed of the UAV even during data transmission (see the link [[https://youtu.be/6i5](https://youtu.be/6i5) RmCsChBw]([https://youtu.be/6i5](https://youtu.be/6i5) RmCsChBw) (accessed on 20 May 2024)). It is important to highlight that the results shown in the video prioritize the flight demonstration of the UAV and the programs that are executed in each stage, as well as their results, remembering that the monitoring stations are only responsible for emulating the buoy measurements, which is why they are not shown in detail in the video. Table 3 shows the results obtained from these tests, carried out with LoS transmission, the time it took to receive the package, and the quality parameters with which the message was received (dBm and SNR). It is important to mention that the dBm and SNR values in the table are the average of the signal quality values of the 20 messages that make up the package. Thus, with the information in Table 3, an interpolation of the data was performed, obtaining the results shown in Figure 6.  
In future work, we intend to compare the transmission results considering two scenarios: in the first, by collecting the data with the UAV at a constant speed (without stopping over the monitoring station). In contrast, in the second, the UAV would be kept hovering over the monitoring station until the information was collected. Eventually, the speed of the UAV was limited in terms of data transmission time and transmission range; for this reason, several tests were carried out with the system. The station sent three data packages, which were collected at different speeds from the UAV. From the above, Table 3 was constructed, with which it can be determined that at a flight speed of 10 m/s, a transmission diameter of 690 m is required to transmit the complete data package. However, at a transmission distance of 700 m, the dBm and SNR values tend to interrupt data communication; comparatively, with a flight speed of 7 m/s, a transmission diameter of 470 m is required. Furthermore, the range distance is an essential parameter in collecting information from the stations since it determines the distance that can be traveled in a flight to collect information from a certain number of stations. Therefore, tests were carried out at different speeds to evaluate the battery's performance considering the weight added by the instrumentation placed for the reception and storage of data; the results are shown in Table 4.  
With the data shown in Table 5, it was verified that the transmission range with the transceivers can be greater than 800 m; however, as the distance increases, the signal quality is affected. The signal intensity (dBm) decreases as the UAV moves further away, indicating that signal intensity is lost (see Figure 7). On the other hand, as the UAV moves away from the transmitting device, the relationship between the amount of noise and the signal (SNR) decreases, even reaching negative values, which means that the signal contains mainly noise and not the original message [28] (see Figure 8). From a 500 m LoS between the UAV and the monitoring stations, the SNR presents negative values, indicating that there is a greater presence of noise in the signal. Therefore, the routine in charge of verifying the integrity of the data requests that more shipments be made. Additionally, the subsystems are subject to various disturbances that affect signal quality. Therefore, the transmission time loses its linear trend (see Figure 9).