20 November 2009 Method for decrease of the centroid error of star image caused by stellar spectrum
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Abstract
Due to the residual chromatic aberration of lens in star tracker, the position accuracy of the star image decrease with the increase of the field of view (FOV). The spectral distribution characteristics of guide star catalog including about 4600 stars are analyzed statistically, and the function model of stellar spectrums is established in this paper. The centroid position for each of the guide star images is a function of its color type and the radial distance to the center of the FOV. The principle of calibration of the centroid error is to make the weighted polynomial, and use a least square fitting approach to obtain the best values of the position errors compensatory parameters for star image considered in a wide field of view (FOV) and with different color temperature. As an example, at the 2.5 DEGREES (FOV) star position errors for Spectral types F, G and K are 10.80μm, 6.5174μm and 4.3479μm respectively. The star position RMS error is reduced from 1.06 pixels to 0.13 pixels, after implementing the spectral compensation scheme for the lens system of a star tracker.
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Hai-bo Liu, Hai-bo Liu, Ji-chun Tan, Ji-chun Tan, Shui-hua Huang, Shui-hua Huang, Xiu-jian Li, Xiu-jian Li, Li Liu, Li Liu, Wei Tan, Wei Tan, } "Method for decrease of the centroid error of star image caused by stellar spectrum", Proc. SPIE 7511, 2009 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Systems, 75110U (20 November 2009); doi: 10.1117/12.839991; https://doi.org/10.1117/12.839991
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