Energy-Efficient UAV-SAR Based ISAC Target Area Imaging with Beamforming Design and Trajectory Optimization

Integrated Sensing and Communication (ISAC) technology has emerged as a key enabling technology for future communication systems. In the context of target area detection, Unmanned Aerial Vehicle-Synthetic Aperture Radar (UAV-SAR) based ISAC system that shares a common physical infrastructure and spectral resource, can significantly enhance spectrum and energy efficiency, making it a crucial area of research. However, existing studies on UAV-SAR based ISAC system imaging for target detection remain limited. In this paper, we propose an optimization method for sequential convex optimization based on linear state space approximation, designed for rotary UAV that simultaneously perform SAR imaging and information backhaul. The method locally optimal maximizes the UAV's energy efficiency by optimizing the UAV's trajectory, speed, beamforming, and power distribution while ensuring the fulfillment of key constraints, including SAR imaging SNR (signal-to-noise ratio) thresholds, UAV power limits, and minimum/maximum speed requirements. Numerical results demonstrate that, compared to other benchmarks, the trajectory of proposed method signifi-cantly enhances the energy efficiency of the UAV.