Abstract: Leveraging vast orbital resources and reduced satellite manufacturing and launch costs, the low-orbit satellite Internet has entered a stage of vibrant development, In this paper, centered on the two important trends of satellite-terrestrial convergence and the integration of communication, navigation and remote sensing, we propose a satellite-terrestrial converged network architecture from the perspectives of access, transport , and core networks. Subsequently, we carefully analyze solutions of direct-to-handset satellite communication or typical applications of space-ground convergence, and put forth the pivotal technologies for direct-to-handset satellite communications towards the 6th generation of mobile communication network. Finally, a comprehensive discussion on the network architecture, key technologies, and potential application scenarios regarding with the integration of low-orbit satellite communication, navigation, and remote sensing is presented.

Key words: low earth orbit satellite network, satellite-terrestrial convergence, the integration of communication, navigation and sensing