基于冷原子重力仪的船载动态绝对重力测量实验研究

Ship-borne dynamic absolute gravity measurement based on cold atom gravimeter

冷原子重力仪正逐渐向小型化、动态化、实用化方向发展,将其应用于深远海绝对重力测量及水下长航时、高精度导航具有十分重要的意义.而目前冷原子重力仪多数尚处于实验室静基座或准静基座测量状态,难以满足动态应用场景下的重力测量需求,因此对冷原子干涉重力测量进行“由静到动”的相关研究十分迫切和关键.本文分析了动态测量的基本原理,给出了冷原子重力仪与加速度计组合测量的基本方法,搭建了一套基于冷原子重力仪和惯性稳定平台绝对动态重力测量系统,并采用冷原子重力仪与传统加速度计组合测量方式,开展了船载动态测量实验.首先,在实验室静态环境下进行了约40 h的连续绝对重力测量,对冷原子重力仪的性能进行初步评估,灵敏度为447µGal/√Hz(1 Gal=1 cm/s^(2)),长期稳定度可达2.7µGal.在此基础上开展船载实验,测量船在湖上以约4.6 kn的速度航行,采用重复测线的方式开展了船载绝对动态重力测量.经评估,四条重复测线的内符合精度为2.272 mGal,四个航次外符合精度分别为2.331,1.837,3.988和2.589 mGal.最后,针对实验结果,对可能存在的问题进行进一步分析与总结.本实验研究为海洋绝对重力动态测量提供了前期验证与技术方案参考.

Cold atom gravimeter is gradually developing towards miniaturization,dynamics and practicality.It is of great significance to apply it to deep and far sea absolute gravity measurement and underwater long navigation time and high-precision navigation.At present,most cold atom gravimeters are still in the state of laboratory static base or quasi-static base measurement,which is difficult to meet the gravity measurement needs in dynamic application scenarios.Therefore,the research on"static to dynamic"of cold atom interferometric gravity measurement is very urgent and key.In this paper,the basic principle of dynamic measurement is analyzed,the basic method of combined measurement of cold atom gravimeter and accelerometer is given,a set of absolute dynamic gravity measurement system based on cold atom gravimeter and inertial stabilization platform is built,and the ship-borne dynamic measurement experiment is carried out by using the combined measurement method of cold atom gravimeter and traditional accelerometer.Firstly,the continuous absolute gravity measurement for about 40 h is carried out in the laboratory static environment to preliminarily evaluate the performance of the cold atom gravimeter.The sensitivity is 447µGal/√Hz,and the long-term stability can reach 2.7µgal.On this basis,the ship-borne experiment is conducted,the survey ship sails on the lake at a speed of about 4.6 kn,and the ship-borne absolute dynamic gravity measurement is carried out by means of repeated survey lines.After evaluation,the internal coincidence accuracy of the four repeated survey lines is 2.272 mGal,and the external coincidence accuracy values of the four voyages are 2.331,1.837,3.988 and 2.589 mGal respectively.Finally,according to the experimental results,the possible problems are further analyzed and summarized.This experimental study provides preliminary verification and technical scheme reference for marine absolute dynamic gravity measurement.