为了最小化激光干涉式绝对重力仪中落体旋转引入的重力加速度测量误差,提出了一种基于落体悬吊的光心质心间距调校方法,结合落体的外部结构,搭建了一套简易高效的落体调校装置。该装置采用光电自准直仪测量落体悬吊状态下的俯仰角,可实现对落体质心位置的高准确度调节,进而完成对落体光心质心距的调校。对装置的测量不确定度进行了评估,得到落体光心质心距测量的合成标准不确定度为18.85μm。最后在NIM-3A型绝对重力仪上进行实验验证。结果表明,悬吊法调校落体的光心质心距优于20μm。若落体旋转角速度控制在0.02rad/s以内,则落体引入的重力加速度的误差优于1μGal。
Abstract
To minimize measurement error of gravity acceleration induced falling body rotation in absolute gravimeter based on laser interferometry, a method for adjusting the distance between center of mass(COM) and the optical center(OC) based on falling body suspension was proposed. Combined with the external structure of falling body, a simple and efficient falling body adjusting device was built. The device adopted photoelectric autocollimator to measure the pitch angle of the falling body in suspension state, which can adjust the position of COM of falling body, and then completed the adjustment of the distance between COM and OC. The uncertainty of the systematic measurement was also evaluated, and the synthetic standard uncertainty of the distance measurement was 18.85μm. Finally, the falling bodies adjusted by suspension method was put into the NIM-3A absolute gravimeter for experimental. The results show that the distance between COM and OC is better than 20μm, which is in line with the estimated uncertainty results. If the angular velocity of the falling body is controlled within 0.02rad/s, the measurement uncertainty of the gravitational acceleration introduced by the falling body rotation is better than 1μGal.
关键词
重力加速度 /
绝对重力仪 /
光心质心距 /
落体 /
悬吊法
Key words
gravity acceleration /
absolute gravimeter /
distance between center of mass and optical center /
falling body;suspension method
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基金
中国计量科学研究院基本科研业务费重点领域项目(AKYZD2002-3)
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