Spatial orientation measuring instrument precision evaluation method based on single-star projection

Abstract

The invention discloses a spatial orientation measuring instrument precision evaluation method based on single-star projection. The method comprises the specific steps of: firstly, calculating an observation vector of each star point in a measuring instrument body system according to the position coordinates of the star points and a calibration coefficient; secondly, searching an inertial vector corresponding to the star point according to a navigation star number, and projecting the inertial vector to the instrument body system according to an attitude matrix, so as to obtain a projection position vector of the navigation star in the system; thirdly, calculating the deviation of the projection position vector relative to the observation vector, and calculating a three-axis error angle according to a measuring instrument imaging model; and finally, calculating a weight coefficient corresponding to each identified star in the frame of star map according to star magnitude, and comprehensively evaluating the measurement precision of the frame according to a multi-star attitude determination principle. Compared with a polynomial fitting method based on multi-frame analysis and a difference method based on adjacent two-frame analysis, the influence of a spacecraft platform on the method is minimum, and the evaluation result is closest to the measurement precision of an instrument.

Description

technical field [0001] The invention relates to an on-orbit accuracy evaluation method of a space pointing measuring instrument, in particular to an accuracy evaluation method based on a single-star projection position error. Background technique [0002] The basic principle of space extremely high-precision pointing measurement instruments (at least sub-arc-second precision) is to use image sensors to capture star images, and obtain the spacecraft's three-axis inertial attitude and target pointing information through star image processing. With the development of technology, its precision index has broken through the arcsecond and entered the sub-arcsecond precision level, and some products can even reach the extremely high precision level of one hundred to dozens of milliarcseconds. [0003] When the extremely high-precision pointing measurement instrument is tested on the ground, it is difficult to accurately evaluate its true accuracy index due to the influence of equipm...

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Problems solved by technology

[0003] When the extremely high-precision pointing measurement instrument is tested on the ground, it is difficult to accurately evaluate its true accuracy index due to the influence of equipment and the environment (such as jitter, temperature and humidity, atmospheric seeing, etc.); if it is in a real orbital space environment In this case, although ground influence factors can be ruled out, due to the influence of spacecraft platform shake and other factors, the traditional evaluation methods of optical axis pointing accuracy of instruments - polynomial fitting method and adjacent difference method are difficult to evaluate extremely high-precision indicators

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