综合PNT场景增强系统研究进展及发展趋势

定位导航授时（positioning navigation and timing,PNT）是国家重要战略基础设施，目前中国已经建立了完善的北斗天基增强系统、地基增强系统、低轨增强系统，室内外定位技术蓬勃发展，但声光电磁等多种定位技术手段在全球导航卫星系统（global navigation satellite system,GNSS）拒止环境受到诸多限制，在深空、深地、深海三深空间综合PNT依然面临许多困难。近年来，数字孪生、实景三维等战略逐渐落地，三维场景为提高综合PNT的完好性、连续性、可用性提供了新的机遇。对综合PNT场景增强国内外技术现状进行了系统梳理，总结了综合PNT场景增强系统面临的挑战，阐述了综合PNT场景增强系统建设主体、服务层次、系统架构等基本框架，展望未来中国的综合PNT体系是以北斗PNT为核心，天基增强、地基增强、低轨增强、场景增强多源信息集成的服务于全空间的综合PNT智能服务体系。

A Survey of Scene-Based Augmentation Systems for Comprehensive PNT

Positioning navigation and timing (PNT) is the nation's critical infrastructure. At present, China has established the relatively complete ground-based augmentation systems, satellite-based augmentation systems and low earth orbit(LEO) satellite-based augmentation system for comprehensive PNT. Although indoor positioning on a contemporary smartphone is booming, including Wi-Fi, bluetooth, magnetic field fingerprinting, and so on, these existing methods still cannot provide high quality PNT services for the whole area, such as underground, indoor space, and underwater. Recently, the key technologies of real three-dimensional model and digital twin model received more and more attention. The information of geographic scene presents unrecalled opportunities to improve the robust availability, continuity, high accuracy and reliability of comprehensive PNT system. First, we introduce the state-of-the-art of related studies of scene-based augmentation systems, including scene-based PNT systems augmentation.Second, we summarize the challenges and present the definition and basic concept of the scene-based augmentation systems for comprehensive PNT. Next, the system architecture, construction units and hierarchical service mechanism of scene-based augmentation systems is proposed. Finally, we forecast the development trend of scene-based augmentation systems for comprehensive PNT. The China comprehensive PNT system should be BeiDou-centered and include ground-based augmentation systems, satellite-based augmentation systems (SBAS), LEO SBAS and scene-based augmentation systems for comprehensive PNT as auxiliary augmentation systems. It has the ability to provide intelligent PNT services in whole area.