This book presents a collection of peer-reviewed original research papers from the 4th International Summit on Large-Scale Application of Beidou, held in September 2025 in Zhuzhou, Hunan, China. The topics covered in the book include, but are not limited to: Integrated PNT system and new technologies, Satellite navigation and augmentation technology, Space-time Reference System and Orbit Determination Technology, Satellite navigation signal and terminal technology, Navigation Technologies for Unmanned Systems, as well as Deep space and lunar navigation technology. The book showcases the latest research achievements in methodologies, algorithms, and applications within the field of positioning, navigation, and timing (PNT), incorporating advancements in artificial intelligence (AI) technologies. This book serves as a valuable reference for researchers, engineers, and graduate students alike.

Yang Changfeng, an academician of the Chinese Academy of Engineering, serves as the chief designer of the BeiDou Navigation Satellite System. He has long been engaged in the overall design and engineering management of the BeiDou system.

Xie Jun, a researcher at the China Academy of Space Technology, is the deputy chief designer of the BeiDou Navigation Satellite System. He primarily focuses on research in satellite navigation technology and related fields.