Evaluation of UAV-Based ISAC SAR Imaging: Methods and Performances

This paper seeks to demonstrate the functionality of an Integrated Communication and Sensing (ISAC) system operating within the sub-6 G Hz frequency range for Synthetic Aperture Radar (SAR) imaging from an Unmanned Aerial Vehicle (UAV). The primary goal of this research is to determine the viability of generating SAR imagery of the environment while adhering to practical constraints and parameters defined by contemporary communication standards. These parameters include aspects such as maximum transmitted power, carrier frequency, occupied bandwidth, Pulse Repetition Frequency (PRF), the number of sub-carriers employed, and more. The paper provides a detailed explanation of the Orthogonal Frequency Division Multiplexing (OFDM) signal transmitted by the base station. Furthermore, it compares two potential methods for range-compressing the signal. An analysis of the Noise Equivalent Sigma Zero (NESZ) is proposed under classical line-of-sight conditions and in a more challenging environment, demonstrating the system's ability to detect targets under snow cover. The conclusion includes the presentation of simulated Impulse Response Functions (IRF) under various assumptions and actual SAR images of the environment captured using a UAV equipped with a software-defined radar (SDR).