Calculation of Swath Width and Swath Displacement for Uncrewed Aerial Spray Systems

Highlights Recent research has focused on the use of Uncrewed Aerial Spray Systems (UASS) for their potential to fill the gap between crewed aircraft and ground application equipment. The spray distribution in swath is highly variable to the point that using the typical metric of uniformity alone to define swath can no longer apply, we present a method that considers dose and uniformity. The swath was rarely found to be directly beneath the flightline, the swath displacement and offsetting can be significant and larger than the assumed swath width. This paper presents the development of an evidence-based, repeatable mathematical solution to the determination of swath width and swath displacement for UASS for calibration and targeting purposes. Abstract. Recent research has focused on the use of Uncrewed Aerial Spray Systems (UASS) for their potential to fill the gap between crewed aircraft and ground application, with UASS being able to be used over less accessible areas than ground equipment, being more appropriate to treat smaller, dispersed targets, and typically available at reduced cost and complexity when compared to crewed aircraft. However, there is limited literature focusing on the proper setup and use of these systems. The objective of this study was to design and conduct a series of large-scale, conceptually linked studies to provide data that is used to guide system optimization and the development of predictive models. An uncrewed system coupled with three nozzle types covering three droplet size classifications was used to conduct swath characterization and drift trials designed to establish effective swath widths, deposition variability, swath displacement, and drift. System and nozzle type, along with nozzle position and wind direction, significantly impacted the spray deposition patterns within and downwind of the effective swath. The spray distribution in a swath is highly variable, to the point that using the typical metric of uniformity alone to define swath can no longer apply. In addition, the swath was rarely found to be directly beneath the flightline, and swath offsetting can be significant and larger than the assumed swath width. An iterative solution has been developed that uses a combination of effective dose and uniformity to define swath width. The offsetting of the swath due to interactions with ambient air has also been defined using the Center of Deposition. The aim is to be able to distinguish between in-swath deposition and drift. The approach to defining swath width and the displacement of the swath is presented. The goal is to develop a real-time onboard navigation system that can reset the flight line in response to wind-driven swath displacement. This allows increased deposition within the target zone and reduces off-target losses. Keywords: Aerial application, Offset, Swath displacement, Swath width, Unmanned aerial spray system.