Study On Technique Of Star Spectral Simulator Based On Digital Micromirror Device

High-precision and very high-precision star sensors are the hotspot of international research.Before they work in orbit,they must be tested on the ground for performance and accuracy calibration to ensure their high working accuracy.However,due to the lack of high accuracy in ground accuracy testing and experimental verification,the simultaneous simulation of star magnitude and spectrum of star points seriously restricts the development of high precision star sensor technology.For this reason,this paper studies and designs a DMD-based star simulator spectral simulation system,which provides a technical way for high-precision spectral simulation of star simulator.The design scheme of spectrum modulation system for dynamic star simulator based on DMD is completed.The Czerny-Turner structure is used as the initial spectral dispersion structure,and the structure optimization and aberration correction are carried out to obtain the dispersion structure satisfying the spectral modulation conditions.The principle of DMD spectral modulation and the principle of arbitrary spectral synthesis are analyzed.Based on this,the calibration of initial spectral fitting element interval is completed,and the fitting of specific color temperature curve is realized.At the same time,the spectral coupling module composed of the optical mixing module and the beam collimation module is completed to realize the coupling of the spectral modulation system and the high contrast mosaic display system.Based on the analysis of the traditional splicing display method of dynamic star simulator,a double PBS splicing display optical system and a single NPBS splicing display optical system are optimized respectively.Through the analysis of the difficulty and energy requirement of the system installation,the double PBS splicing display optical system with simple structure and high energy utilization is selected,and the high contrast display of navigation star map is realized.The experimental results show that the spectral simulation accuracy is better than 4%,the modulation spectral resolution is 5 nm,and the spectral width is 460-680 nm.Continuous simulation of 3000K~9000K color temperature curve.At the same time,it can simulate 0 Mv ~+6 Mv continuously,and the accuracy of magnitude simulation is less than +0.5 Mv.All meet the technical requirements of dynamic star simulator.