Development and Verification of LQG based Attitude Determination and Control Algorithm of Cube-satellite 'SNUGLITE' using GPS and Multiple Sensors

摘要

Nowadays, various research has been done for cubesat, a nano-satellite small and inexpensive compared to general satellites. It is used for educational reasons, cost reduction, and various other missional reasons. Most of the cubesats have been launched for low earth orbit (LEO) where orbit environments such as eclipse and various disturbance torques, such as gravity gradient torque, solar radiation torque, and aerodynamic torque exist. Since cubesats have small moment of inertia (MOI) causing it to be sensitive for disturbance torques existing in the low earth orbit. Therefore, designing attitude control algorithm is important not only for the survival, but also for successful mission. This paper will examine the attitude determination and control system (ADCS) algorithm for cubesat SNUGLITE (Seoul National University GNSS Laboratory satellITE) and show how the proposed algorithm satisfies the ADCS requirements considering the operation scenario. The ADCS is composed of 3-axis MEMs gyroscope sensor, 2-axis coarse photodiode type sun sensors, 3-axis MEMs magnetometer, dual frequency GPS receivers, and 3-axis magnetic torquers. The EKF (Extended Kalman Filter) and LQG (Linear Quadratic Gaussian) controller has been chosen for ADCS algorithm for SNUGLITE. Furthermore, this paper will provide SILS (Software In the Loop System) that simulates the space environment to verify the proposed ADCS algorithm.