SIMULASI PENGENDALIAN SIKAP DAN ORBIT SATELIT LAPAN-A4 PADA MANUVER STATION KEEPING SUN-SYNCHRONOUS ORBIT

• Main Author: Ernesto B Sihombing, Epafras
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/61756
• Institution: Institut Teknologi Bandung

Station keeping is one of the processes of a satellite's mission to maintain the orbit throughout its lifespan due to external perturbations from the outer space environment that could aect the orbital parameters. On LAPAN-A4, this station keeping maneuver is needed to keep its orbit as a Sun-Synchronous Orbit (SSO) with little changes of equatorial passing local time. SSO is charac- terized by its nodal precession rate of 360°/year as a combination of the orbital semi-major axis, eccentricity, and inclination. One of the strategies that could be done is an inclination change maneuver to maintain the nodal precession rate to correspond the SSO characteristics. Inclination change maneuver with a xed thruster on the satellite needs satellite's attitude control to orient the or- bital velocity change during the maneuver. Thus, an attitude control system to fulll the satellite's attitude requirement during the station keeping maneuver is needed. In this research, a numerical model of LAPAN-A4 satellite attitude dynam- ics has been modeled using Simulink with rigid body assumption and reaction wheel as the actuator. Orbital dynamics model of the satellite that allows an orbital parameters changing maneuver using a thruster has been modeled as well. Control trials using various methods of PID, Pole Placement, and Lin- ear Quadratic Regulator (LQR) has been conducted and LQR is obtained as the most optimal control method that allows optimizing control input and minimiz- ing error between observed and reference values. Control system using LQR controller has been designed and implemented on a previously planned SSO station keeping case and fullls the required orbital parameter changes.