# Unmanned Aerial System-Based Data Ferrying over a Sensor Node Station Network in Maize
## 5 Summary and Conclusions  
Six designs of UAS-enabled data ferrying systems with IoT-enabled communication using radios were proposed based on design criteria and constraints. A final design of a data ferry was selected which comprised of a long-range radio wireless communication protocol, an external power source, a multi-rotor UAS, and memory storage. The selected design of the UAS data ferry was tested over a WSN in a maize field in eastern Nebraska during the latter portions of the 2020 and 2021 growing seasons. Each stationary sensor node station installed in maize contained three soil water content sensors, one infrared radiometer, and one secondary radio. CSR at various UAS heights above the stationary nodes (in 2020) and lateral distance (in 2021) from the nodes was investigated. Three experimental trials during the 2020 growing season demonstrated that a 100% CSR occurred when the UAS maneuvered directly over the node station at a height of 31 m above the ground. Henceforth, the UAS was flown at a height of 31 m above the ground during the 2021 growing season to investigate the effect of lateral distance of the UAS data ferrying from the node station on the CSR. For the nine experimental trial events (flight days) during the 2021 growing season, the CSR was higher (80% average) when the UAS was directly over the node station (0 m lateral distance) and at a lateral distance of 38 m from the node station. The CSR was lower when the UAS was 76 m laterally away from the node station (60% average). In general, the lower CSR at higher heights and further distances from the node station was potentially due to the interference from the maize canopy and plant moisture and the location of the antenna in the enclosure; during late reproductive physiological stages when plant water is lower a higher CSR was achieved for all lateral distances as the crop progressed to physiological maturity. Substantial progress was made in understanding the UAS-based data ferrying system and the potential of the UWSN system to improve agronomic decision making. Future studies to investigate the scalability, adoptability, and optimum deployment scheme (along with mounting an RGB-infrared imaging camera for aid in agronomic decision making, and antenna location) for the proposed data ferrying design could strengthen the applicability of the UWSN system. **Author Contributions:** Conceptualization, J.S., Y.G. and D.M.H. ; Methodology, J.S. and M.S.M. ; Validation, J.S., Y.G., D.M.H., C.M.U.N., E.W.-S. and S.I. ; Formal Analysis, J.S. ; Investigation, J.S., Y.G., C.M.U.N. and D.M.H. ; Resources, C.M.U.N., D.M.H. and Y.G. ; Data Curation, J.S. ; Writing--Original Draft Presentation, J.S. ; Writing--Review and Editing, E.W.-S., Y.G., M.S.M. and D.M.H. ; Supervision, Y.G. and D.M.H. ; Project Administration, C.M.U.N., D.M.H. and Y.G. ; Funding Acquisition, C.M.U.N., Y.G. and D.M.H. All authors have read and agreed to the published version of the manuscript. **Funding:** The funding for this research was provided by a grant from the USDA NIFA Agricultural and Food Research Initiative (Award Number 2017-67021-26249) and the Daugherty Water for Food Global Institute at the University of Nebraska. Additional support was received from the Hatch Act (USDA NIFA, Accession Number 1009760) and the Department of Biological Systems Engineering at the University of Nebraska-Lincoln. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Informed consent was obtained from all subjects in the study. **Data Availability Statement:** Data is contained within the article. No additional data was created or analyzed in the study. **Acknowledgments:** The authors thank [PERSON], [PERSON], and [PERSON] for input in the experimental design; [PERSON] for reviewing the manuscript; [PERSON], [PERSON], [PERSON], and [PERSON] for assistance with the data collection; and [PERSON] and his team from the University of Nebraska's Eastern Nebraska Research and Extension Center for their cooperation and help with field operations.