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

Abstract

With growing usage and demand for the global freshwater supply, there is an increasing need for technologies that facilitate water conservation and environmental stewardship in irrigated agriculture. Toward this end, recent demonstrations of Internet of Things (IoT) sensors have revealed the value of wireless soil moisture content sensors. However, existing wireless solutions often employ above-ground wireless communication modules that physically interfere with routine farming operations. Underground wireless network solutions are severely challenged by the large radio-frequency (RF) propagation loss through soil. This paper presents a method that overcomes both problems by employing completely buried underground IoT sensors and communication modules with UAS (uncrewed aircraft system) mounted LoRaWAN gateways. The UAS mounted LoRaWAN gateway eliminates the need for any in-field base stations and also allows the LoRa enabled sensors to transmit data over short distances with very low energy. Field tests were carried out using this approach to serve as a proof of concept. The RSSI (received signal strength indicator) demonstrates that the proposed solution has good communication link margin and a significantly larger communication range than is necessary for reliable operation. Moreover, this solution is easy to build, scalable, cost-effective, and can be implemented in a highly power efficient fashion.INDEX TERMS internet of things (IoT), long range radio (LoRa), scientific irrigation scheduling, soil moisture monitoring, uncrewed aircraft system (UAS)

Energy Efficient Underground Wireless Sensor Networks for Disaster Analysis in Hill Stations

“…The soil moisture level is detected through uncrewed aircraft system(UAS). The energy efficiency is evaluated comparing various state of art approach but still the drawback in the system is complex hardware's and its maintenance creates burdens [10].…”

Relationships between Soil Moisture and Visible–NIR Soil Reflectance: A Review Presenting New Analyses and Data to Fill the Gaps

“…In this case, the value of normalisation is clearly demonstrated: in Figure 18b it is apparent that no 1:1 relationship exists between MC and the normalised difference in reflectance at 1860 nm and 1920 nm, while linear (Figure 18c) and exponential (Figure 18d) models may be well fitted to the normalised data in the domains of 5-25% MC or 0-55% MC, respectively. The relevant equations for these models are: y = 57.34x − 7.53 (10) y = 10.75 × e 2.1723x − 10.85 (11) Despite having different functional forms (linear and exponential) while including overlapping data, both of the normalised models perform well. The linear model has a slightly improved fit compared to the exponential model, with an R² of 1.00 and 0.97, SE of 0.01 and 0.04, and reduced chi-squared of 0.16 and 0.95, respectively.…”

“…The measurement and monitoring of soil MC is thus relevant to many real-world contexts and research in this field is ongoing in multiple disciplines. For those applications and many other purposes, there is clear value in the development of rapid, cost-effective, broadly applicable methods for soil moisture monitoring [9][10][11].…”

Internet of Underground Things in Agriculture 4.0: Challenges, Applications and Perspectives

“…Ref. [70] presented field tests carried out with a gateway mounted on an UAV, which received the soil moisture data transmitted by some sensor nodes buried at 30 cm deep. The communications were performed in LoRa at 916 MHz.…”