Unmanned aerial vehicles (UAVs) face a lot of security challenges due to the openness of their wireless communication. In this paper, we investigate how to improve the security of wireless communication when the UAV is utilized as a wireless relay. We consider a new scenario where the dual UAVs are employed cooperatively to transmit confidential information and an eavesdropper whose actual position is unknown attempts to eavesdrop on the information illegally. We propose an optimization problem for the average secrecy rate under multiple constraints. The optimization problem we proposed is non-convex and complicated. We design an iterative algorithm that jointly optimizes the trajectories and transmit power to make the average secrecy rate maximized via the block coordinate descent and successive convex approximation techniques. The feasibility of this method is verified by numerical simulation.

由于其无线通信的开放性，无人机（UAV）面临许多安全挑战。在本文中，我们研究了当无人机用作无线中继时如何提高无线通信的安全性。我们考虑一个新的场景，其中协同使用双UAV传输机密信息，而实际位置未知的窃听者试图非法窃听该信息。我们提出了多个约束条件下的平均保密率的优化问题。我们提出的优化问题是非凸且复杂的。我们设计了一种迭代算法，通过块坐标下降法和连续凸逼近技术共同优化轨迹和发射功率，以使平均保密率最大化。