In satellite communication system, various operations take place. Among which, the main operations are orbit controlling, altitude of satellite, monitoring and controlling of other subsystems.

A satellite communication consists of mainly two segments. Those are space segment and earth segment. So, accordingly there will be two types of subsystems namely, space segment subsystems and earth segment subsystems. The following figure illustrates this concept.

As shown in the figure, the communication takes place between space segment subsystems and earth segment subsystems through communication links.

Space Segment Subsystems

The subsystems present in space segment are called as space segment subsystems. Following are the space segment subsystems.

• AOC Subsystem
• TTCM Subsystem
• Power and Antenna Subsystems
• Transponders

Earth Segment Subsystems

The subsystems present in the ground segment have the ability to access the satellite repeater in order to provide the communication between the users. Earth segment is also called as ground segment.

Earth segment performs mainly two functions. Those are transmission of a signal to the satellite and reception of signal from the satellite. Earth stations are the major subsystems that are present in earth segment.

We will discuss about all these subsystems of space segment and earth segment in following chapters.