Three-dimensional cooperative localization via space-air-ground integrated networks

The space-air-ground integrated network (SAGIN) combines the superiority of the satellite, aerial, and ground communications, which is envisioned to provide high-precision positioning ability as well as seamless connectivity in the 5G and Beyond 5G (B5G) systems. In this paper, we propose a three-dimensional SAGIN localization scheme for ground agents utilizing multi-source information from satellites, base stations and unmanned aerial vehicles (UAVs). Based on the designed scheme, we derive the positioning performance bound and establish a distributed maximum likelihood algorithm to jointly estimate the positions and clock offsets of ground agents. Simulation results demonstrate the validity of the SAGIN localization scheme and reveal the effects of the number of satellites, the number of base stations, the number of UAVs and clock noise on positioning performance.