Orbit Shifting Analysis Satellite Telkom 4 with Cowell and Encke Method Caused by Perturbation

Satellites are objects that revolve around other objects in certain period of revolution and rotation. There are two types of satellites, natural and artificial satellites. There are several types of artificial satellites based on their use such as weather satellites, military satellites, science education satellites, and communications satellites. Artificial satellites can follow a position according to the movement of the earth, which is called the geostationary orbital position. When a satellite is in a geostationary orbit position, its speed will be relatively low, allowing the position satellite to be moved. The surveillance area has been regulated in ITU-R Rec. S. 484. about the control area tolerance limit of less ±0,5° for operational fixed satellite. In this case, the mobile satellite requires a lot of power and shortens the life of the satellite. Predicting the orbital displacement time interval involves two orbital methods, namely Cowell method and Encke method. Both of these methods can be used to determine the length of time that occurs when the satellite is moved. This study aims to compare which method can determine time intervals more accurately. The advantage of this research is that there are two methods that can be used to determine the time interval of the satellite orbitals. Quantitative comparative research method for field survey through comparison of applied research in main control satellites. The results of the comparison of the two methods will be used for orbital purposes, combined with positional and mathematical factors to determine the duration of orbital shift.