Optical system design of miniaturized star sensors: a method based on an evaluation function

The star sensor, recognized for its high-precision attitude measurement capabilities, faces traditional challenges related to its substantial size and elevated power consumption when utilized in micro-satellites. This research centers on the miniaturization of the optical system within the star sensor. It formulates theoretical approaches for achieving miniaturization and elucidates the principles governing optical power distribution, subsequently proposing an evaluation function, denoted as Q, to quantify the degree of miniaturization of the optical system. Through an analysis involving multiple lens groups, the efficacy of the evaluation function Q has been successfully validated. Guided by the aforementioned theoretical framework and the evaluation function Q, a compact optical lens assembly for a miniaturized star sensor has been developed, featuring a focal length of f=30mm, an F-number of 2.3, a spectral range spanning from 500 to 800 nm, and an overall system length of merely 23.95 mm. Furthermore, the system is designed to be athermalized, ensuring consistent imaging quality across a temperature range of -40^∘C∼60^∘C. The findings suggest that the miniaturization theory and the evaluation function Q serve as effective tools for guiding the design of compact optical systems, thereby enhancing the applicability of star sensors in domains such as micro-satellites.