Aerial ISAC: A HAPS-Assisted Integrated Sensing, Communications and Computing Framework for Enhanced Coverage and Security

In this paper, we propose a framework for a non-terrestrial ISAC system, where a high-altitude platform station (HAPS)-mounted full duplex (FD) ISAC base station (BS) is deployed to deliver communication services to multiple user equipment (UEs) and, at the same time, sense multiple targets. Moreover, the ISAC-BS offloads part of the sensed data to a dedicated edge server for computation purposes. Additionally, an unmanned aerial vehicle (UAV) is deployed to transmit jamming signals aimed at degrading the reception quality of malicious targets or potential eavesdroppers identified through the sensing process. A multi-objective optimization problem is formulated to jointly optimize the transmit/receive beamforming and UAV trajectory to maximize the communication sum spectral efficiency under radar performance, security, offloading, and power constraints. Since the formulated problem is non-convex, we use alternating optimization (AO), semi-definite relaxation (SDR), and successive convex approximation (SCA) approaches to solve it. Simulation results show that the communication and radar achieved rates from the proposed algorithm outperforms the cases of using non-optimized UAV’s trajectory and using the Rayleigh-quotient method to design the receive beamforming vectors.