I. Overview The satellite communication system is actually a kind of microwave communication. It uses satellites as relay stations to forward microwave signals and communicate between multiple ground stations. The main purpose of satellite communication is to achieve "seamless" coverage of the ground due to satellites. Working on hundreds, thousands, or even tens of thousands of kilometers of track, the coverage is much larger than the average mobile communication system. As an effective supplement and guarantee for communication methods such as cellular and radio, its advantages and irreplaceability are becoming more and more significant. Establish and improve the emergency communication security system, improve the communication system network, establish a communication system that combines wired and wireless, and the basic network and mobile communication network to ensure the communication guarantee for emergency response work. With the development of technology, satellite communication is now an indispensable means of emergency communication. It has already played an important role in important tasks such as earthquake and counter-terrorism, and will play an immeasurable role in the future.
2.  satellite communication system features
Ø Wide coverage: Satellite mobile communication has a wide coverage and flexible networking, which is suitable for sites with scattered sites and far away from urban and terrestrial communication;
Ø Mobility and real-time: Emergency communication vehicles or portable stations can quickly arrive at the scene according to emergency needs, with short installation and commissioning time, and can quickly establish command and communication means;
Ø High reliability: In addition to the satellite transponder on the communication link, there is no intermediate link on the transmission line, and the stations are independent of each other and do not affect each other. The network management center can also centrally monitor the operating status of the system and equipment failures, and can detect the failure of the satellite terminal station in time and take measures;
Ø Strong resilience: Compared with terrestrial satellite communication systems, satellite communication is less likely to be damaged by natural disasters, especially floods, and has a flexible structure without relaying. Even if individual stations fail, it will not affect the normal communication of other stations;
Powerful: The ability to use satellite communications can provide a variety of functional services. Such as large-span, large-scale, long-distance image transmission, video conferencing, etc. In addition, satellite communication can also be used as an alternate means of terrestrial communication systems to ensure smooth and reliable communication.