Attitude Determination and Control System of a CubeSat in Suborbital Flight

Abstract: The Bistable Boom Dynamic Deployment (B2D2) experiment aims to successfully demonstrate the deployment of a 2 meter self-deployable boom in order to offer an efficient alternative for small satellites to conduct higher quality magnetic field measurements. The boom will be placed in a free falling unit, following the CubeSat standard. To obtain reliable results from the deployment, the tumbling rate of the free falling unit must be reduced to acceptable levels. Two cameras located in the free falling unit will record the boom deployment, meaning that they will need to be pointed in the opposite direction of the sun vector to obtain optimal results. To meet these requirements an Attitude Determination and Control System (ADCS) is needed. In this thesis the design, implementation and testing of the ADCS is presented. For B2D2 experiment the ADCS has been developed using a feedback loop where three reaction wheels are used to control the orientation. The attitude will be determined by means of five coarse sun sensors, a three axis magnetometer and an angular rate sensor. The attitude is estimated in two stages: first a deterministic approach computes the instantaneous attitude and the result is then complemented with an multiplicative extended Kalman filter. Finally, a non-linear control law is implemented to command the actuators and close the loop.