A REVIEW OF THE CURRENT UNMANNED AERIAL VEHICLE SPRAYER APPLICATIONS IN PRECISION AGRICULTURE

. Unmanned Aerial Vehicles (UAVs) are becoming more broadly used for improving agricultural spraying applications. However, compared with the nearly 100 years of data accumulated on manned aerial applications, UAV sprayers are relatively new, and associated technologies are in the early stages of development. The objective of this paper is to give a comprehensive review of the current UAV spraying platforms with a comparison to manned aerial sprayers and a discussion of their application, performance, and efficiency. A total of 213 peer-reviewed and non-peer-reviewed articles, extension papers, government websites, and company websites were reviewed and cited in this study. We also discuss factors that could influence the effectiveness of aerial spraying applications, such as release height, wind speed, vortex strength, and droplet size. Finally, we review the latest UAV sprayers available worldwide and present technology gaps in those platforms. We highlight areas that require improvement, particularly in autonomous navigational controllers and spraying systems.