Enhancing AAV-to-Ground Communication Security With the Proceed-Hover-Return (PHR) Approach

Downlink communications with multiple ground targets using autonomous aerial vehicles (AAVs) as a base station is critical across various fields. However, the presence of potential eavesdroppers introduces significant challenges that must be addressed to ensure the effectiveness and security of these operations. In this work, we investigate the AAV-to-ground communications in the presence of an eavesdropper, focusing on enhancing physical layer security by maximizing the secrecy rate. We propose a Proceed-Hover-Return (PHR) approach, which optimizes the AAV's trajectory, flight time, speed, and hovering duration to achieve the highest possible secrecy rate during communication with ground users. Our numerical results demonstrate the effectiveness of the PHR scheme, which consistently outperforms the fixed-time baseline approach, with particularly significant improvements for users located farther from the eavesdropper. This work provides essential insights into designing secure and efficient AAV communication systems in scenarios involving multiple ground users and potential eavesdroppers.