Simulation of Tracking Process and Communication Link with Satellite

What is done in this paper is simulation of telemetry and telecommand communication between satellite and earth station as what exists in real earth station. Three software: Satellite predictive motion software, Monitoring and Control (M&C) software, processing Software are used in the simulation. Satellite predictive motion software uses orbital equation extracted from Two Line Elements (TLE) to generate tracking elevation and azimuth angles of satellite. These angles as text file are input of M & C software. The M & C software has four modes as simulation mode, online mode, test mode and emergency mode. In simulation mode Acquisition Of satellite (AOS), Loss Of Satellite (LOS) and Pass Time (PT) are seen. The angles are produced and transferred to antenna servo system for moving antenna to desirable direction. Time of simulation is controllable and received signal level is displayed simultaneously. In this mode when satellite is observable, the telecommand can be send. In online mode all explained capabilities are valid except changing of time. In test mode antenna axis could move in desirable velocity and acceleration. In the other hand, when the satellite becomes lost, the system enters to emergency mode for searching of satellite. In the normal mode after receiving the telemetry data by M & C software this data as text file transferred to processing software. Processing software by protocol which accepted by satellite (HDLC based) recognizes the first and the end of telemetry frame and then extracts and displays the parameters. The telemetry parameters include online and offline data.