Data Collection from Buried Sensor Nodes by Means of an Unmanned Aerial Vehicle

Abstract

The development of Wireless Underground Sensor Networks (WUSNs) is a recent research axis based on sensor nodes buried a few dozen centimeters deep. The communication ranges are, however, highly reduced due to the high attenuation of electromagnetic waves in soil, leading to issues of data collection. This paper proposes to embed a data collector on an Unmanned Aerial Vehicle (UAV) coming close to each buried sensor node. The whole system was developed (sensor nodes, data collector, gateway) and experimentations were carried out in real conditions. In hovering mode, the measurements on the RSSI levels with respect to the position of the UAV highlight the interest in maintaining a high altitude when the UAV is far from the node. In dynamic mode, the experimental results demonstrate the feasibility of carrying out the data collection task while the UAV is moving. The speed of the UAV has, however, to be adapted to the required time to collect the data. In the case of numerous buried sensor nodes, evolutionary algorithms are implemented to plan the trajectory of the UAV optimally. To the best of our knowledge, this paper is the first one that reports experiment results combining WUSN and UAV technologies.

Soil Moisture Monitoring Through UAS-Assisted Internet of Things LoRaWAN Wireless Underground Sensors

“…The buried sensors and the gateway aboard the UAS use LoRa-based wireless communication. A similar work [26] has been published by Cariou et al; however, there are some important differences between our work and [26]. The operating frequency in our work is 916 MHz whereas in [26], the operating frequency is 868 MHz.…”

“…A similar work [26] has been published by Cariou et al; however, there are some important differences between our work and [26]. The operating frequency in our work is 916 MHz whereas in [26], the operating frequency is 868 MHz. Our sensor node was buried at a depth of 0.3 meters whereas the sensor node in [26] was buried at a depth of 0.15 meters.…”

“…The operating frequency in our work is 916 MHz whereas in [26], the operating frequency is 868 MHz. Our sensor node was buried at a depth of 0.3 meters whereas the sensor node in [26] was buried at a depth of 0.15 meters. Generally, sensor nodes buried deeper into the ground can prove more beneficial as they are more likely to be cleared from farming machinery operations.…”

“…Generally, sensor nodes buried deeper into the ground can prove more beneficial as they are more likely to be cleared from farming machinery operations. In our work, from experimental data and path loss analysis, we have demonstrated that the relative antenna orientation of the buried sensor and the above ground gateway has little significance in communicating data packets -which in [26] has not been presented. We have also presented our analysis of percentage packet loss with varying distances which in [26] has been mentioned to be done in future work.…”

“…In our work, from experimental data and path loss analysis, we have demonstrated that the relative antenna orientation of the buried sensor and the above ground gateway has little significance in communicating data packets -which in [26] has not been presented. We have also presented our analysis of percentage packet loss with varying distances which in [26] has been mentioned to be done in future work. In [26], it has been shown that the RSSI (received signal strength indicator) values after a particular horizontal distance is higher at a higher altitude -the impact of the soil on the propagation of the signal has been attributed as the reason for this -whereas we have elaborated on the mechanisms of signal propagation from soil to air from an electromagnetic perspective and also using an electromagnetic simulation.…”