Large Field and High Precision Optical System for Star Tracker

In order to address the existing star tracker's problem of large size and on-orbit gluing, a new telemetric optical system is designed in this paper. And the optical system has a large field of view, a high precision and a small size. Firstly, the optical system's engineering requirements are described and its design specifications are calculated. Based on the calculated results, the initial structure and materials of this optical system are determined. Secondly, the optimization design of structure is conducted with the design principles of optical system, and the imaging performance of this optical system is evaluated by analyzing spot diagram, modulation transfer function, encircled energy and ray aberration curves. Finally, the optical system which has six lenses is optimized to have a field of view 44.7 degrees x 44.7 degrees and a total length 36.9mm. Its distortion accounts for 0.51% of pixel size, and its displacement of centroid from chief ray is equal to 7.89% of pixel size. The simulation results evince that the optical system has a large field of view, a high precision, a small size and less lenses. And the on-orbit gluing problem is eliminated by using this optical system. Moreover, the optical system's simple structure can also benefit its manufacturing and assembly process.