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Design of kalman filter based attitude determination and control algorithms for a LEO satellite

Efendioğlu, Gamze
The design of different attitude controllers by using reaction wheels and magnetic rods as torque sources and the design of a multi-sensor integrated navigation system are developed for a three-axis stabilized Earth-orbiting microsatellite and presented in this thesis. Firstly, the fundamental parameters relevant to satellite attitude determination are presented, such as attitude sensors and actuators, space environmental effects, coordinate frames, satellite dynamic/kinematic equations with control components. These parameters are also used to set satellite linear and nonlinear mathematical models. Reaction wheels and magnetic torque rods are used to generate the required control torque for the purpose of providing attitude control. The momentum dumping effects of magnetic rods are also implemented to mathematical models and controlled by the help of Earth Magnetic Field. Kalman Filter based attitude estimations with PID, LQR and SMC controllers were designed to support satellite orientation with respect to a given reference attitude. In addition to these controllers, a feedback controller is also designed for stabilizing the satellite angular velocity after separating from launcher. Simulating of multi-sensor navigation sensors, satellite mathematical model and controller models under various internal and external disturbances and measurement noises are carried out by means of MATLAB/Simulink software tool. The results obtained from the simulations with related approaches were compared and analyzed.