A greenery-based solution for low-noise delivery hub for unmanned aerial transport

Unmanned Aerial vehicles are nowadays involved in a wide range of applications, such as surveillance, safety control, scientific research, and commercial activities. The logistics industry, in particular, is showing a substantial interest in a partial transition of the last-mile delivery service from ground to air transport. A key point to make this scenario feasible resides in the design of delivery hubs to serve the surrounding areas, thus overcoming the logistical difficulties of a door-to-door delivery while respecting the strict regulations in terms of noise.
The proposed paper deals with the study and design of an urban hub for package delivery that uses natural elements such as hedges to limit the noise footprint associated with drone operations by exploiting the shielding capabilities of natural barriers. Some constraints driving the design are identified, leading to a tentative conceptual design. 
The acoustic property of a sample hedge is evaluated using an equivalent porous medium approach, informed by parameters estimated by image processing of the external surface of the hedge. Eventually, the model is used in coupled BEM-FEM simulations of simplified designs. Preliminary results show encouraging noise reductions in the areas surrounding the hub.