船载高精度星敏感器安装角的标定

星敏感器测量船体姿态精度与星敏感器与甲板之间的安装角标定精度密切相关。本文介绍了船载星敏感器的相关坐标系及安装角的定义,建立了船载星敏感器蒙气差修正模型,提出了一种船载高精度星敏感器安装角标定方法。船进坞坐墩时,船载经纬仪通过拍摄方位标确定航向,星敏感器通过星图识别获得视场内星点的赤经、赤纬,构成地心惯性系参考矢量,经岁差、章动、极移、船位等修正,得到各恒星在惯导地平系下的参考矢量。然后,根据蒙气差模型对星点逐个修正俯仰角,重构惯导地平系下的参考矢量。最后,依据姿态确定算法原理,解算星敏感器安装矩阵,求解安装角。实验表明,使用该方法可使方位角、俯仰角的标定精度达10"以内。该方法有效发挥了星敏感器指向精度高的优点,改善了程序自动化程度,提高了船体姿态测量精度。

Calibration of installation angle for high accuracy shipboard star sensor

Ship attitude measurement accuracy based on star sensors is relative to the calibration accuracy of the installation angle between star sensor and ship desk. This paper introduces the coordinate system of the shipboard star sensor and the definition of installation angle. Then, it establishes a model to correct the atmospheric refraction of the sensor and proposes a calibration method for installation angle of the high accuracy shipboard star sensor. When the space TT & C ship docks in shipyard, shipboard theodolite determines the course of the ship by shooting the azimuth mark, and star sensor obtains the ascension and declination of the stars in the field of view by star recognition to construct the star reference vectors with respect to inertial space. After correction of precession, nutation, pole shift and ship position, the star reference vectors with respect to Inertial Navigation System(INS) horizontal coordinate system are obtained. According to the atmospheric refraction correction model, each star in the field of view corrects its pitch angle and reconstructs its star reference vector with respect to INS horizontal coordinate system. Finally, star sensor installation matrix is calculated based on the principle of attitude determination algorithm, and then three installation angles are solved. Experiment results show that the calibration accuracy of azimuth and pitch using proposed method reach less than 10". The proposed method is based on the higher pointing accuracy of the star sensor and improves automatic programming and measuring accuracy of ship attitudes.