Transmission principle of air ground linkage emergency command system: This scheme adopts 4G private network (VSF-OFCDM non center same frequency networking technology) and 4G public network compatible emergency wireless communication mode. The audio and video signals collected by the audio and video acquisition equipment of UAVs and individual soldiers are converted into digital signals through the equipment. The portable receiving equipment receives the audio and video signals of front-end individual soldiers and UAVs, and then transmits them back to the command center through the 4G public network transmission module in the portable receiving equipment. VSF-OFCDM wireless network realizes full two-way data, audio and video transmission, non line of sight transmission, and supports high-speed mobile transmission of command vehicles at a speed of no less than 350 km/h. At the same time, the system can also be seamlessly linked with 4G (3G) communication and satellite communication. The three transmission modes are combined to be compatible and backup each other, so that there is no dead end in communication.