基于冷原子重力仪的绝对重力动态移动测量实验

Experiment on dynamic absolute gravity measurement based on cold atom gravimeter

动态重力测量可以提高重力场的勘测效率,对基础地质调查、资源勘探、地球物理研究等具有十分重要意义.本文基于冷原子重力仪、惯性稳定平台和牵引动力装置搭建了一套绝对重力动态移动测量系统,并开展了绝对重力动态测量实验.首先测量了不同牵引速度下的垂向振动噪声功率谱,理论分析了其对动态重力测量的影响;其次评估了不同牵引速度对原子干涉条纹对比度和直流偏置量的影响,分析了动态环境下的振动补偿效果;在最大牵引速度为5.50 cm/s、最大振动幅度为0.1 m/s^(2)的情况下,实验上仍能基于振动补偿技术恢复原子干涉条纹.在此基础上,通过开展不同T下的原子干涉条纹测量,评估了动态测量环境下的绝对重力值,在校正完系统误差并减去绝对重力初始值后得到的测量结果为(–1.22±2.42)mGal(1 Gal=0.01 m/s^(2)).最后,通过与静态环境下的绝对重力测量值进行比较,发现两者基本吻合.本文开展的绝对重力动态移动测量实验有望为车载动态绝对重力测量提供数据参考.

Dynamic gravity measurements can improve the survey efficiency of the gravity field,and can play an important role in implementing the basic geological surveys,resource exploration,and geophysical research.Based on cold atom gravimeter,inertial stabilization platform and the movable vehicle device,a system for dynamically measuring absolute gravity is built,and the dynamic measurement experiments are carried out.Firstly,the noise power spectra of the vertical vibration are measured at different moving velocities,and the influence of such a vibration on the measurement of absolute gravity is analyzed theoretically.Besides,the influence on the contrasts and offsets of the atomic interference fringes are evaluated from different moving velocities,then the effect of vibration compensation in the dynamic measurement environment is analyzed.When the maximum moving speed is 5.50 cm/s and the maximum vibration amplitude is 0.1 m/s^(2),the atomic interference fringes can still be rebuilt based on the technology of vibration compensation.On this basis,the atomic interference fringes are obtained at different values of T and different moving velocities,then the absolute gravity value in the dynamic measurement environment is evaluated.After the correction of the systematic system and subtraction by the initial value of absolute gravity,the final measured result is(–1.22 ±2.42) mGal.Finally,the experiment on the static absolute gravity is conducted,and the two values are found to be not much different from each other through comparing the static measurement data with the dynamic measurement data.The experiment of dynamic absolute gravity measurement in this paper may provide the helpful reference data for the dynamic absolute gravity measurement with moving vehicles.