What is a Satellite Communication System?

1. What is satellite communication?

Satellite communication is to use communication satellites as relay stations to forward radio waves to realize communication between two or more earth stations. Satellite communication is an advanced communication method that combines modern communication technology with aerospace technology and is controlled by a computer.

VSAT communication has the advantages of large coverage area, long communication transmission distance, communication frequency bandwidth, large capacity, stable communication line, good quality, fast network construction, flexible and flexible, can work in broadcast mode, facilitate the realization of multiple access connections, and has many advantages such as communication cost independent of communication distance.

A communication satellite is an artificial earth satellite that receives and forwards relay signals and is used as a communication medium. According to the communication mode, it can be divided into active and passive.

Because passive communication satellites only reflect radio waves, high-power transmitters, large-sized receiving antennas and highly sensitive amplifying and receiving equipment are required, and the technical requirements for transmitting and receiving equipment are high and the cost is expensive, so it is difficult to use; 

All currently operating satellites are active. Communication satellites mostly use low orbit, large elliptical or geosynchronous orbit. At present, the vast majority of communication satellites use geosynchronous orbits, which run in a circular orbit around the earth about 36,000 km above the earth's equator. A certain area seems to be stationary, also called geostationary satellite, also called geostationary satellite, and its orbit is called geostationary or geostationary orbit.

The VSAT satellites we often mention and several communication satellites launched by China are all satellites in geostationary orbit.

2. Satellite communication system

Several global mobile satellite communication systems that are familiar to most readers in recent years, the International Mobile Communication Satellite (IC0), Iridium (Iridium) and Globalstar (Globalstar) systems belong to the medium orbit (MEO, 5000km ~ 15000km), low orbit (LE0, 500km ~ 1500km) satellite communication system.

According to the working area, communication satellites can be divided into international communication satellites, domestic communication satellites and regional communication satellites. According to the application field, it can be divided into radio and television satellites, tracking satellites, data relay satellites, defense communication satellites, aviation satellites, navigation satellites, tactical communication satellites, fleet communication satellites and military data forwarding satellites.