Research On Lens Design And Assembly Technology Of Star Sensor

As a commonly used attitude sensor,the star sensor has the advantages of high measurement accuracy and autonomous navigation,so it is widely used in military,civil,marine and other fields.The optical system is the core component of the star sensor,which affects the speed of the subsequent processing and the accuracy of positioning.The optical system optical system alignment is an important part to ensure the image quality.Therefore,the research on the lens design and alignment methods of the star sensor has important significance.In order to improve the relative aperture of the system and broaden the spectral range,based on the functional requirements of the satellite platform and the existing optical systems,a star sensor optical system with excellent performance need to be designed.The sensor sensitivity model is analyzed to determine the design parameters of the optical system.According to the determined parameters,a star sensor optical system is designed.The optical system consists of a protective window,7 spherical lenses and a filter.The spectral range is 500~800 nm,the focal length is 50 mm,the relative aperture is 1/1.25,the field of view is 8.45°×8.45°(diagonal angle of view is 11.96°),and the total length is 83.33 mm.The system adopts an image telecentric design,which reduces the measurement error caused by the image surface defocus and other factors.After the optimization,the distortion is less than 0.5%,the centroid color deviation is controlled within ± 2 ?m,the energy concentration(3×3 pixels)is greater than 80%,the maximum magnification chromatic aberration is-0.073 ?m,and the spots of the on-axis field and the off-axis are basically the same.Compared with the optical system at different temperatures,the change of the focal length is small,which verifies the principle of athermalization design.The imaging quality of the lens is good.The aignment technology affects the performance of the optical system.The commonly used alignment methods for refractive lens like the star sensor lens are studied in this paper,including: direct assemble method,centering metal-turning assembly method,centering assembly and adjustment method.Furthermore,a new automatic centering assembly technology was researched and the related experiments were performed.The experiment results show that the measurement accuracy of this technology can reach the order of micrometers,which can be applied to the assembly of the star sensor optical system and other high-precision optical systems.The new technology could reduce the difficulty of optical assembly and improve the assembly accuracy of the optical system.