Research on the space-air-ground integrated emergency communication auxiliary system for urban rail transit

With the continuous expansion of urban rail transit networks and the increasing passenger flow, the importance of emergency management and assurance within transit systems is growing. At present, emergency communication in urban rail transit sections primarily relies on terrestrial wireless communication technologies, including TETRA systems, LTEM systems, and customized 5G public networks. These systems operate independently, lacking automatic switchover mechanisms to other systems in case of failure, making it challenging to maintain communication continuity and availability during communication breakdowns or disasters. This paper proposes and studies a Space-Air-Ground Integrated Emergency Communication Auxiliary System. By introducing Beidou Satellite (BDS) transceivers and internetwork conversion devices at stations and control centers, the system achieves interoperability with existing TETRA, LTE-M, and customized 5G public network systems. It ensures reliable transmission and reception of emergency information by automatically switching to backup networks or BDS short messages when terrestrial networks fail. This significantly enhances the emergency command and dispatch capabilities of urban rail transit systems during emergencies, providing vital support for passenger safety.