Research on precision windowed track mode for in-orbit calibration on star tracker

摘要

Implementation of an in-orbit calibration is an effective approach to reduce position error of individual star spot down to arcsec on star tracker. However, without knowledge of variance errors of some error sources, the reduction of such errors to what extent is unclear leading to in-orbit correction inefficiency. Based on Cramer Rao Lower Bound(CRLB) theory, we obtain the minimum variance error of position and make an accurate definition of precision windowed track mode for in-orbit calibration. After that, the error constraints on proper motion, velocity aberration, drift in focal length and other factors are studied in details. Imposing proper restrictions on those parameters, in-orbit correction of star tracker could approach CRLB accuracy.