When UAVs Meet ISAC: Real-Time Trajectory Design for Secure Communications

TL;DR

This paper presents a real-time UAV trajectory optimization method for secure ISAC communications, utilizing EKF-based tracking of a ground user and an iterative algorithm to maximize secrecy rate.

Contribution

It introduces a novel EKF-based tracking and a non-convex trajectory design algorithm for secure UAV-based ISAC systems.

Findings

Accurately tracks ground user location in real-time

Achieves a favorable trade-off between legitimate and eavesdropper rates

Demonstrates near-optimal secrecy rate performance

Abstract

The real-time unmanned aerial vehicle (UAV) trajectory design of secure integrated sensing and communication (ISAC) is optimized. In particular, the UAV serves both as a downlink transmitter and a radar receiver. The legitimate user (Bob) roams on ground through a series of unknown locations, while the eavesdropper moves following a fixed known trajectory. To maximize the real-time secrecy rate, we propose an extended Kalman filtering (EKF)-based method for tracking and predicting Bob's location at the UAV based on the delay measurements extracted from the sensing echoes. We then formulate a non-convex real-time trajectory design problem and develop an efficient iterative algorithm for finding a near optimal solution. Our numerical results demonstrate that the proposed algorithm is capable of accurately tracking Bob and strikes a compelling legitimate vs. leakage rate trade-off.