Potentiality of UAV-based ISAC SAR Imaging

Abstract:
This paper aims to illustrate the capabilities of an Integrated Communication and Sensing (ISAC) system operating within the sub-6 GHz frequency range for Synthetic Aperture Radar (SAR) imaging from an Unmanned Aerial Vehicle (UAV). The primary objective of this contribution is to ascertain the feasibility of producing SAR imagery of the environment while adhering to the practical constraints and parameters dictated by contemporary communication standards. These parameters encompass factors such as maximum transmitted power, carrier frequency, occupied bandwidth, Pulse Repetition Frequency, number of sub-carriers employed, and more. Within the paper, we present a comprehensive description of the Orthogonal Frequency Division Multiplexing (OFDM) signal transmitted by the base station. We then compare two possible ways to range-compress the signal backscattered by the scene. Additionally, we propose an analysis of the Noise Equivalent Σ Zero (NESZ) in classical line-of-sight conditions and also in a more challenging environment, thereby proving the capability of the system to detect targets under the snow. We conclude by showing simulated Impulse Response Functions (IRF) under different assumptions and real SAR images of the environment acquired using a UAV and a software-defined radar (SDR) mounted as a payload.