As a new pillar of China’s economic growth, the booming low-altitude economy hinges on core enabling technologies including positioning, navigation and wireless communication. The Beidou-5G integrated spatiotemporal network, a novel infrastructure combining the Beidou Navigation Satellite System (BDS) and 5G, delivers integrated communication and navigation services essential to low-altitude operations and fuels sound development of the low-altitude economy. Centered on this network and taking Beidou-5G integrated base stations as core nodes, this paper systematically investigates low-altitude UAV communication-navigation integration basics. It compares native BDS and 5G features, exposes drawbacks of standalone deployment, and presents the network’s overall framework. Key discussions cover integrated base station hardware, 5G control-plane broadcast technology and network layout schemes. Benchmarking rival base station designs proves 5G control-plane broadcast excels in low latency, massive concurrency and robust security. This paper assesses the network’s support for low-altitude scenarios from five perspectives: full-coverage high-precision time synchronization, centimeter-level positioning improvement, multi-aircraft collaborative sensing, low-altitude weather and interference surveillance, and upgraded communication performance. It further discusses integration and construction hurdles, then forecasts trends such as communication-sensing-navigation fusion, advanced Positioning, Navigation and Timing (PNT) services and innovative network operation modes. The final conclusion: large-scale rollout of Beidou-5G integrated base stations fixes key low-altitude bottlenecks-unreliable positioning, weak airspace oversight and safety risks-by establishing a converged digital spatiotemporal platform. This research offers valuable guidance for technical tuning and industrial rollout of the low-altitude economy.