CommSAR: Enabling Bidirectional Communication in SAR Imaging Satellites via Shared Waveform
Yimin Zhao , Zhenning Li, Hao Pan , Hua Li, Minhao Cui , Jie Xiong , Yihai Wei, Yang Liu, Haonan Zhao, Mohan Zhang, Weibo Wang, Guihai Chen , Kaiyu Liu, Linghe Kong
Abstract
Low Earth Orbit (LEO) Synthetic Aperture Radar (SAR) satellites conventionally rely on dedicated communication links, which impose prohibitive hardware and resource overhead as constellations scale. This paper presents CommSAR, a novel bidirectional communication system that reuses existing SAR imaging waveforms to enable communication without degrading the satellite's imaging performance or requiring satellite hardware modifications. For the downlink, data are embedded by modulating the starting frequency offset of imaging waveforms, preserving the waveform structure and imaging quality. For the uplink, we propose a compact, low-cost programmable metasurface to replace conventional large, expensive antennas, significantly lowering the barrier for dense ground station deployment. To handle extreme LEO dynamics, we employ a reverse-slope waveform as a pilot to compensate for mobility-induced effects. We implement a ground station prototype of CommSAR and validate it using an in-orbit commercial SAR satellite and a UAV SAR platform. Experimental results show that CommSAR preserves imaging resolution without degradation while achieving average bidirectional data rates of 105 kbps (downlink) and 120 kbps (uplink), significantly outperforming the state of the art.
Cite (BibTeX)
@inproceedings{zhao2026commsar,
title = {CommSAR: Enabling Bidirectional Communication in SAR Imaging Satellites via Shared Waveform},
author = {Zhao, Yimin and Li, Zhenning and Pan, Hao and Li, Hua and Cui, Minhao and Xiong, Jie and Wei, Yihai and Liu, Yang and Zhao, Haonan and Zhang, Mohan and Wang, Weibo and Chen, Guihai and Liu, Kaiyu and Kong, Linghe},
booktitle = {Proceedings of the ACM SIGCOMM 2026 Conference},
year = {2026}
}