Star map data based method for measurement of in-orbit precision of star sensor

Abstract

A star map data based method for measurement of in-orbit precision of a star sensor. The single-frame static star map data obtained by the star sensor is utilized for measure the key performances such as in-orbit pointing accuracy and viewing angle of the star sensor; a quaternion estimation algorithm (QUEST), which converts the eigenvalue solution into the solution of a root of a fourth-order equation to speed up, is employed to obtain an optimal attitude matrix Aq; then according to the attitude matrix Aq and the identified n navigational stars, conducting back calculation to obtain the theoretical position of each navigational star on the image sensor, wherein the theoretical position is the theoretical point of intersection (xit, yit) of the primary optical axis of the star sensor and the interface; calculating the errors between the theoretical positions of the star points (xit, yit) and the measured actual positions of star points, wherein the actual star point position is the actual point of intersection (xi, yi) of the primary optical axis of the star sensor and the interface; and calculating a mean value of the errors and converting the mean value to an equivalent angle value, so as to obtain the precision of the star sensor. Compared to the commonly used in-orbit comparison method, the method provided by the invention eliminates the influence of the errors of time alignment and installation matrix between the star sensors, and reaches higher measurement accuracy.

Description

technical field [0001] The invention relates to a method for measuring key performances such as on-orbit pointing accuracy of a star sensor based on star map data of the star sensor itself, and belongs to the field of on-orbit measurement of spacecraft. Background technique [0002] At present, it is generally believed that the star sensor is the absolute attitude measurement device of the spacecraft that can provide the highest precision. Its working principle is to use the star in space as a reference object, image the space star target through the detection unit of the star sensor, and perform a series of processing such as centroid extraction, star map recognition, star tracking, and attitude calculation on the captured star map , to obtain the instantaneous boresight pointing information of the star sensor, and then through the corresponding coordinate transformation, finally output the azimuth information of the spacecraft body coordinate system. [0003] Because the ...

AI Technical Summary

Problems solved by technology

Due to the high precision of the star sensor, the requirements for the position information of the navigation star are also relatively high, and the on-orbit verification generally only verifies some space adaptability of the star sensor. Most of the measurements are obtained indirectly through comparison with similar data of the spacecraft platform. Due to the influence of time alignment and installation matrix errors, the measurement accuracy is not high enough.

According to the survey of existing patent achievements, there is no research on how to use the star map obtained by the star sensor itself to improve the accuracy of the star sensor's on-orbit precision measurement

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