AUTHOR=Yao Lihao , Fan Bin , Qin Honglei , Xian Deyong , Wang Mengli , Gu Boyun , Chen Sumin , Wang Changhong , Wang Xuyu , Shen Jiemin , Jiang Dongfang , Wei Heng , Yu Haoyuan , Liu Bingjie , Shao Shuai TITLE=Overview of the system-level anti-jamming capability and developmental challenges of low-earth-orbit signal-of-opportunity JOURNAL=Frontiers in Physics VOLUME=Volume 13 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2025.1569385 DOI=10.3389/fphy.2025.1569385 ISSN=2296-424X ABSTRACT=Signal-of-Opportunity (SOP) navigation based on Low-Earth-Orbit (LEO) satellite constellations has increasingly become a research hotspot. Due to the large number of LEO satellites, wide spectrum coverage, and strong signal power, LEO satellite Signal-of-Opportunity (LEO-SOP) inherently possess strong anti-jamming capabilities. However, there has been limited in-depth research on the overall system-level anti-jamming capability of LEO-SOP. This paper reviews the current state of research on LEO-SOP and anti-jamming technologies, introduces the principles of LEO-SOP Doppler-based positioning and receiver operation, and analyzes the system-level anti-jamming capability of LEO-SOP. Additionally, it explores the key challenges in the development of LEO-SOP anti-jamming technologies and discusses future research directions. This study aims to provide insights into the development prospects of LEO-SOP anti-jamming technologies, promote further research and development efforts, and establish a solid technical foundation for the secure application of LEO-SOP. Ultimately, ensuring the integrity and resilience of LEO-SOP systems against complex threats.