基于双干涉仪的自由落体绝对重力测量  

Free-fall absolute gravity measurement based on double interferometers

作　　者：冯金扬[1] 吴书清[1] 李春剑[1] 粟多武[1] 于梅[1] 

机构地区：[1]中国计量科学研究院,北京100029

出　　处：《光学精密工程》2015年第10期2740-2746,共7页Optics and Precision Engineering

基　　金：国家质量监督检验检疫总局技改量传项目(No.AJG1403);中国计量科学研究院基本科研业务费专项资金资助项目(No.AKY1406)

摘　　要：为了避免用光学干涉法测量自由落体绝对重力过程中落体旋转对测量结果准确度的影响,提出了基于双干涉仪的绝对重力测量方法。介绍了落体旋转影响绝对重力测量结果的机理,提出了对同时测量的两组干涉仪数据进行融合处理的方法。根据预先设定的重力值,双干涉仪中落体上、下反射棱镜光心与质心垂直方向的初始高度差,以及随机生成的每次测量对应的角速度序列和振动引起的上、下干涉仪重力测量偏差序列,进行了仿真计算。结果表明:光心-质心的距离为2.5mm的双干涉仪通过数据融合处理得到的重力测量结果的偏差约为0.5μGal,标准偏差约为0.3μGal,与现有调校落体光心-质心的方法得到的结果相当。选择合适的上、下棱镜光心-质心距离可以更好地消减落体旋转对测量结果的影响,将其分别设计为±3mm时,用双干涉法数据融合得到的重力值偏差小于1μGal,满足相关领域对精密重力测量的需求。To avoid the effect of falling body rotation on measurement accuracy for free-fall absolute gravity measurement based on optical interferometry,a novel method by using two interferometers was proposed.Firstly,the effect mechanism of falling body rotation on absolute gravity measurements was introduced and a data fusion method using data derived from an absolute gravimeter with two simultaneously measured interferometers was presented.Then simulation experiments were carried out according to a preset gravity value,the initial perpendicular height difference between the optical center（OC）and the center of mass（COM）in the upper and lower interferometer reflecting prisms in falling body,the randomly generated sequences of rotation angular velocity of falling body and the gravity measurement deviation caused by vibration for the upper and lower interferometer,respectively.The experimental results show that gravity deviation and the standard deviation obtained by data fusion processing from double interferometers with the vertical distance between OC and COM of 2.5mm are about 0.5μGal and 0.3μGal,respectively,which are consistent with that of the existing method by strictly adjustment of the COM of fall body.By properly choosing the distance of OC toCOM for the upper and lower prisms,the effect of rotation can be better reduced.When the distance of the OC to the COM is designed to be±3mm,the gravity value deviation calculated from double interferometer data fusion is less than 1μGal,which meets the requirements of some measurement fields for precise gravity measurement.

关 键 词：绝对重力测量 精密测量 双干涉仪 落体旋转 数据融合 

分 类 号：TH762[机械工程—仪器科学与技术] TH744.3[机械工程—精密仪器及机械]