Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2021, Vol. 18, No. 1, pp. 61-69
Modeling the influence of noise factors on the accuracy of measuring the coordinates of stars
G.A. Avanesov
1 , O.V. Filippova
1 , V.A. Shamis
1 , Ya.D. Elyashev
1 1 Space Research Institute RAS, Moscow, Russia
Accepted: 14.12.2020
DOI: 10.21046/2070-7401-2021-18-1-61-69
Star orientation sensors widely used in modern space technology contain catalogs of the brightest stars in the celestial sphere. To ensure the required number of stars in the field of view of the instrument throughout the entire celestial sphere, it is necessary to use stars in the range of 4–5 magnitudes. The process of measuring coordinates begins in devices with obtaining black and white images of stars in a fairly wide range of the visible and near-IR regions of the electromagnetic radiation spectrum. Then, the images of stars are localized against the background of noises of various physical nature. The measurement process is completed by calculating the position of the energy center of the brightness of the localized group of pixels in the coordinate system of the matrix of the photodetector of the device. At the same time, a large range of integral brightness used in the instruments of stars inevitably leads to significant differences in the accuracy of measuring their coordinates. Simulation and optimization of the conditions for measuring the coordinates of stars of different brightness and spectral class, as well as predicting the accuracy of the result under the influence of noise, allows the calculation and analytical program Star Manager. The paper presents the results obtained with its help, calculated for two versions of devices at different levels of noise exposure.
Keywords: star tracker, astrometry, star catalog, photon noise, instrument noise, random error, background radiation, neighborhood of catalogue stars, centroidal method, catalogue correction
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