Secure Enhancement for RIS-Aided AAV With ISAC: Robust Design and Resource Allocation

This paper investigates the security of a reconfigurable intelligent surface (RIS)-aided unmanned aerial vehicle (UAV) system for integrated sensing and communications (ISAC). A multi-antenna UAV transmits ISAC waveforms to simultaneously detect an untrusted target and communicate with a ground Internet-of-Things (IoT) device in the presence of an eavesdropper (Eve). To reflect practical scenarios where Eve's channel state information (CSI) is unavailable or concealed, we adopt an imperfect-CSI model. Our goal is to maximize the average secrecy rate subject to a sensing quality-of-service constraint by jointly optimizing the UAV trajectory, RIS passive beamforming, transmit beamforming, and receive beamforming. The resulting problem is highly non-convex due to the coupled design variables. We address this challenge with an efficient block coordinate descent framework, in which each block is solved via successive convex approximation built on semidefinite relaxation. Numerical results demonstrate that the proposed algorithm reliably meets sensing accuracy requirements and yields substantial secrecy-rate gains for the IoT link, even under CSI uncertainty, compared with representative baselines.