Designing star trackers to meet micro-satellite requirements

Abstract

Star trackers provide numerous advantages over other attitude sensors because of their ability to provide full, three-axis orientation information with high accuracy and flexibility to operate independently from other navigation tools. However, current star trackers are optimized to maximize accuracy, at the exclusion of all else. Although this produces extremely capable systems, the excessive mass, power consumption, and cost that result are often contradictory to the requirements of smaller space vehicles. Thus, it is of interest to design smaller, lower cost, albeit reduced capability star trackers that can provide adequate attitude and rate determination to small, highly maneuverable, low-cost spacecraft. This thesis discusses the analysis used to select hardware and predict system performance, as well as the algorithms that have been employed to determine attitude information and rotation rates of the spacecraft. Finally, the performance of these algorithms using computer simulated images, nighttime photographs, and images captured directly by star tracker prototypes is presented.