Visual Attitude Determination Strategy for a Nanosatellite Attitude Control Simulator

Attitude determination is critical in maintaining optimal functionality of a CubeSat and ensuring that the mission objectives are achieved. Thus, attitude determination and control (ADC) algorithms must be developed and rigorously tested prior to implementation. A lab-based Nanosatellite Attitude Control Simulator (NACS) is an effective platform for testing mock attitude control algorithms. The onboard inertial measurement unit (IMU) is a key component in providing attitude estimates, implemented for the measurement of body angular rates and orientation. However, readings are susceptible to drift and accuracy degradation, therefore justifying the development of robust measurement and estimation strategies. While using an off-board sensor is a viable option, it is important to ensure that the readings of such a sensor are accurate to a degree that is sustainably comparable to the initial readings of the IMU. This research discusses the development of an optical attitude estimation setup. Deployment of optical attitude estimation through computer vision eliminates drift and provides consistent estimates for the state vector. Attitude estimates from the optical sensor are subsequently used to compare and demarcate the measurements from the IMU. Additionally, this technique can be adapted for other applications requiring similar three-degree-of-freedom tracking. Further areas of work include the implementation of this sensor as part of a sensor fusion framework.