Space-Air-Ground Integrated Networks (SAGINs), which incorporate space and aerial networks with terrestrial wireless systems, are vital enablers of the emerging sixth-generation (6G) wireless networks. Besides bringing significant benefits to various applications and services, SAGINs are envisioned to extend high-speed broadband coverage to remote areas, such as small towns or mining sites, or areas where terrestrial infrastructure cannot reach, such as airplanes or maritime use cases. However, due to the limited power and storage resources, as well as other constraints introduced by the design of terrestrial networks, SAGINs must be intelligently configured and controlled to satisfy the envisioned requirements. Meanwhile, Artificial Intelligence (AI) is another critical enabler of 6G. Due to massive amounts of available data, AI has been leveraged to address pressing challenges of current and future wireless networks. By adding AI and facilitating the decision-making and prediction procedures, SAGINs can effectively adapt to their surrounding environment, thus enhancing the performance of various metrics. In this work, we aim to investigate the interplay of AI and SAGINs by providing a holistic overview of state-of-the-art research in AI-enabled SAGINs. Specifically, we present a comprehensive overview of some potential applications of AI in SAGINs. We also cover open issues in employing AI and detail the contributions of SAGINs in the development of AI. Finally, we highlight some limitations of the existing research works and outline potential future research directions.

翻译：空天地一体化网络（SAGINs）融合了空间网络、空中网络与地面无线系统，是新兴第六代（6G）无线网络的关键使能技术。除为各类应用服务带来显著优势外，SAGINs有望将高速宽带覆盖延伸至偏远地区（如小型城镇或矿区），或地面基础设施无法到达的区域（如飞机或海事场景）。然而，受限于功率与存储资源，以及地面网络设计引入的其他约束，SAGINs需通过智能配置与控制来满足预期需求。与此同时，人工智能（AI）是6G的另一关键使能技术。凭借海量可用数据，AI已被用于解决当前及未来无线网络的紧迫挑战。通过引入AI并优化决策与预测流程，SAGINs可有效适应其周围环境，从而提升多项性能指标。本文旨在通过全面综述AI赋能SAGINs的最新研究，探讨AI与SAGINs的协同机制。具体而言，我们系统梳理了AI在SAGINs中的潜在应用，涵盖利用AI技术时面临的开放性问题，并详述了SAGINs对AI发展的贡献。最后，我们指出现有研究的局限性，并展望了未来潜在的研究方向。