Attitude Control for Nanosatellites
Attitude Control, INPE, Nanosatellite, Extended Kalman Filter.
With advances in nanosatellite research, as an alternative to space exploration, the Instituto Nacional de Pesquisas Espaciais (INPE) is interested in using this new nanosatellite technology in its future missions. This makes it necessary to have a platform on which to study nanosatellite behavior in space. In this context, the following thesis implemented a simulator, composed with a navigation system and a proportional and derivative controller (PD). The sensors used to estimate the attitude were composed of a magnetometer and a solar sensor, simulated by using an ideal model with white noise. To represent the kinematics, the quaternion was adopted and the nanosatellite was a rigid body. In the navigation system, the norm-constrained Extended Kalman Filter had shown itself to be adequate to work with the sensors embedded in the nanosatellite. Thus allowing the estimate of the angular velocity and the quaternion that represents the attitude. For the controller, the values estimated by the Filter were directly used as a control signal, which has the advantage of dealing with the nonlinearities. Different tests were performed to assess the simulator and evaluate the stability of the navigation and control system. The results have demonstrated that the set up is able to stabilize and correct the attitude of the nanosatellite, even in the face of different perturbations, large angles and high angular velocities. Hence, the simulator generates adequate results, allowing it to be used in future nanosatellite studies.