Optical System Design Of Star Sensor

Star sensor is a high precision orientation measurement with star as detection object.It has been widely used in aerospace,aviation,navigation,guidance and other fields.In the practical application of the star sensor,the quality of the optical system will cause the star point extraction error,the stray light in the optical system will cause the star point to be blurred or obscured.This paper designed and simulationed the optical systems of star sensor for the actual demand of obtaining high quality star image.Which will lay a foundation for the development of shipboard star sensor.The main works of this paper are as follows:Analyzed the menthod of determine the design parameters of optical system.Analyzed the demand of a star sensor based on the detection ability of the star sensor,such as the energy of star,the energy on detector,SNR and detection probability of star.The design parameters and performance indicator of the optical system are determined.Analyzed the effects of geometric aberration on the accuracy of the star positioning,It is clear that the geometric aberrations of the optical design such as distortion,coma and vertical chromatic aberration should be focus on.Designed a set of 7 lens optical.Based on the decided design parameters of the optical lens,Make structure selection,optimization of aberration,image quality evaluation,set model and tolerance analysis in ZEMAX,finally designed a double Gaussian optical system which relative aperture is 0.74 and the pupil diameter is34mm.And analyzed the effect of temperature change on the lens.Designed a six cylinder absorption type hood by SolidWorks based on the principles of baffle design and the parameters of the optical lens.Make the optical lens and baffle as a system modeling of optical system.and analyzd the stray light in optical system.stray light suppression ratio reached 10^-10 at 30 degrees.The simulation results show that the optical system was observed in the threshold magnitude 6.5 star,the ability to meet the requirements of stray light suppression.Simulation the star image in three fields of optical lens.Analyzed the offset of the star energy center and the cause of the energy center shift.Simulation the star image and stray lights which caused by scattering of the edge of the view.And simulation the star image and stray lights caused by baffle and coating.Analyzed the energy distribution on the detector,the results show that the baffle structure which designed in this paper meet the demand of stray light suppression,and can observed when the threshold magnitude 6.5 star,The star's energy center offset control in 0.16 pixels in this optical system at 0.707?.