Three-axis Stabilized Satellite Attitude Determination And Control System

In this dissertation, We take a specific meteorological satellite as an example, study systematically the attitude control system for a three-axis stabilized satellite, including the attitude determination algorithms, attitude control laws. The main work is as follows:? Satellite Modeling: Firstly, a variety of attitude representation methods are generalized and analyzed, including their definitions, rules of calculation, kinematics, merits and disadvantages. Then the attitude kinematics and dynamic models about a rigid/flexible satellite are developed employing Quaternion and Euler-Angles representations.? Attitude Determination Subsystem: This part designs in detail an attitude determination subsystem using extended Kalman filter for a specific satellite equipped with infra-red earth sensors and sola sensors and magnetometer, including sensor allocation, algorithm modeling, simulation evaluation, and so on.? An Filtering Algorithm for Satellite Attitude Determination Based on Star-sensor and FOG Combination: We present a filtering algorithm for high precision attitude determination of a specific satellite, and set up the model of the satellite attitude determination by using quaternion. Our algorithm is based on star-sensors and fiber optic gyroscopes (FOG), and utilizes extended Kalman filtering for modifying estimation error of attitude of a satellite and estimation error of gyroscope drift and information fusion. The simulation result shows that this algorithm can provide high accuracy attitude determination with moderate precision gyroscopes, and that the measurement noise of star-sensor and filtering period may influence the attitude determination accuracy.? Attitude Control Subsystem: There are a lot of methods for attitude control of three-axis stabilized satellite, for example, jet-propelled control, flywheel control system, and so on. In accordance with zero momentum flywheel system, based on classic control theory, a PID control law is developed, and control law stability and robustness are analyzed at the same time. To bias momentum flywheel system, based on classic control theory, a PID control law for pitching and non-least phase control law for rolling-yawing are developed.The main contributions of this dissertation: To the small satellite of low cost, we present a algorithm of attitude determination withoutgyroscopes, through the simulation, this algorithm can provide requirements for precision;We present a filtering algorithm based on star-sensors and fiber optic gyroscopes (FOG), the simulation result shows that this algorithm can provide high accuracy attitude determination;In accordance with zero momentum flywheel system, we present a kind of improvement PID control law, through the simulation, it has a better effect.