Optical system of a micro-nano high-precision star sensor based on combined stray light suppression technology

The micro-nano design of a high-precision star sensor is studied. Point source transmittance (PST, the ratio of the irradiance generated by the external field source on the image surface to the irradiance at the entrance pupil) is used as the evaluation index of stray light suppression ability, the stray light suppression theory of star sensors is analyzed, and the mathematical model between stray light suppression ability and detectable magnitude is established. In view of the limited volume of micro-nano star sensors, a new design principle of combined anti-stray-light design of the baffle and optical system is proposed. The high stray light suppression of the micro-nano star sensor is realized by using the imaging optical path design of active stray light suppression and the design of a conical extinction cavity, which breaks through the technical problem of coupling system volume and stray light suppression ability. The results of the simulation and on-orbit experiments show that the star sensor based on the joint stray light technology can achieve a PST of 2×10^-8 at the avoidance angle under the premise of limited optical system volume, and it has a stray light suppression ability of 6.5 magnitude stars.