The Beidou Satellite Navigation System is about to undergo an on-orbit upgrade, a move aimed at significantly enhancing the accuracy of navigation in the future. As the "Bringing Celestial Precision Down to Earth" project progresses, flawless positioning and navigation services have become a reality both within and beyond the confines of the Beijing East Sixth Ring Road Tunnel. This cutting-edge technology is equally adaptable for the refurbishment of both newly constructed and pre-existing tunnels. The Beidou System has set an ambitious goal to finalize the construction of its next-generation system by 2035. At present, the system proudly maintains a constellation of 50 satellites in orbit, excelling in spatial signal transmission, global positioning, speed measurement, and precise timing. Leveraging precise point positioning service signals, it achieves unparalleled high-precision positioning capabilities. The Beidou System has been seamlessly woven into the fabric of national development, offering indispensable services to a diverse array of users.