A FPGA-based approach to attitude determination for nanosatellites

Satellites are becoming an increasingly invaluable tool to aid academic research in a variety of applications. The traditional high cost barrier of space access has led to the development of low cost nano-satellites which emphasise the use of commercial-off-the-shelf (COTS) components and other standardised components. This leads to somewhat lacklustre performance during state estimation, limiting their potential applications however. In order to satisfy strict pointing requirements, there is a need for complex state estimation algorithms to compensate for low accuracy sensors, however traditional microcontroller/processor based approaches often lack the power required to meet the real-time computing deadlines. A novel direct-to-hardware implementation, based on a Field Programmable Gate Array (FPGA), of the Spherical Simplex Unscented Kalman Filter (SSUKF) for state estimation is proposed. The performance of the FPGA implementation is verified via simulation and it is found that the FPGA-based implementation is a superior option to microcontroller-based implementations.