| Star sensor is a high precision attitude measurement instrument, which has been widely used in satellite, missile, shipbuilding and other fields. However, the traditional star sensor is difficult to meet the application requirement of small satellite platform with its shortcomings conclude large volume, heavy weight and large power consumption, so the miniaturization star sensor has to be developed. The optical system’s volume and weight are main part of the star sensor, so the miniaturization design of the optical system is researched in this paper.The parameter of optical system is analyzed and optimized in this paper. Depending on the demand of the Pyramid identification algorithm and signal- noise ratio, the relationship between limiting magnitude and both of baffle size and the Lagrange invariant is analyzed. Based on the relationship, the limiting magnitude and optical system parameters are optimized chosen for miniaturization design.The double gauss configuration is chosen to design the optical lens because of the optical system parameters and image quality requirements. The optical lens is designed with ordinary optical glass and special crystal materials respectively to compare the performance, it shows that the lens with special crystal materials has better performance than the lens with the ordinary optical glass.The main purposes of stray light suppression are suppressing the effect caused by ghost image and stray light outside the field of view. The anti-reflection coating is plated in imaging element to suppress the ghost image. In order to suppress the stray light outside the field of view, the performance and size of 3 baffles are designed and compared. The irradiance caused by earth albedo on the image surface is researched and analyzed.The thermal analysis and tolerance analyzing show this optical system has stable image quality in large temperature variation and also has good machinability.The miniaturization design of star sensor optical lens and stray light suppression system are realized by the optimized chosen of optical system parameters in this paper. The thermal changing and tolerance are researched and analyzed. It lays the foundation for the development of miniaturization star sensor. |
