Star sensor lens and its use method in large-temperature range accurate fixed star azimuth measurement

Abstract

The invention discloses a star sensor lens and a method for large temperature range accurate measurement of azimuth angles of stars by using the same. The star sensor lens comprises a lens barrel, a base, lenses, an optoelectronic image sensor, a diaphragm and a light filter which also serves as a protective window, wherein each two lenses of the four lenses form a group, the two lens groups are arranged on the two sides of the diaphragm symmetrically, object lens expansion rings are arranged at the outer sides of the two lens groups, and a spring ring for restoring and fastening is arranged between the two lens groups. Through an expansion and contraction effect of the expansion rings, the distance between the two lens groups are finely adjusted in a passive mode, so that the focus offset caused by the amount of the fine adjustment between the lenses counteracts that caused by a thermal effect of the lenses and the lens barrel. The focus star sensor lens has excellent thermal stability. According to calculation, the thermal offset delta f / f of the lens focus f is no more than 2*10 within a temperature range from 20 DEG C below zero to 60 DEG C. Under a condition of a large temperature range, the accuracy of the measurement of the azimuth angles of stars of the star sensor lens reaches arc second order.

Description

technical field [0001] The invention relates to a lens of a star sensor and a method for accurately measuring star azimuth angles in a large temperature range. Background technique [0002] The star sensor is one of the commonly used optoelectronic instruments for autonomously measuring the attitude of a spacecraft. The ambient temperature range of the spacecraft is -20°C to +60°C, and the thermal stability of the focal length of the lens has a significant impact on the measurement error of the star sensor. In the star sensors disclosed in the literature, the focal length of the lens changes significantly with the rise and fall of the ambient temperature, resulting in a large error in the star sensor's measurement of the azimuth angle of the star. The following two methods are usually adopted to keep the star sensor with high measurement accuracy under the condition of ambient temperature rise and fall: [0003] (1) The commonly used method to reduce the measurement error ...

AI Technical Summary

Problems solved by technology

[0009] To sum up, the aerospace optical systems reported in the domestic literature have not taken special measures to suppress the focal length thermal deviation caused by temperature changes.

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