基于原子重力仪的车载静态绝对重力测量

Static measurement of absolute gravity in truck based on atomic gravimeter

目前大多数原子重力仪的装置复杂、体积庞大、环境适应性差,不能应用于野外进行绝对重力测量,这限制了原子重力仪的应用领域.本文利用自研的小型化原子重力仪,集成了一套车载绝对重力测量系统.该系统主要由原子重力仪、被动平台隔震系统、位姿平台调平系统、差分GPS测高系统、不间断电源供电系统及车载空调温控系统等组成.首先,本文对该测量系统的车载环境适应性进行了评估,发现在野外40℃高温、8°大倾角普通路面的环境下,该系统仍然能够正常工作;其次,介绍了车载绝对重力测量的实验步骤及数据处理方法,并测量了车头朝向对绝对重力测量的影响.最后,在野外平坦路面上进行了重复测线工作,评估了系统的内符合绝对重力测量精度,结果约为30μGal;在野外大倾角山体路面,通过测量不同海拔高度点的绝对重力值,得到了地球的垂直重力梯度值,约为-231(36)μGal/m.本文结果为野外绝对重力勘测提供了依据.

Currently,most of the experimental apparatuses of atomic gravimeters are complex in structure,large in size,and poor in environmental adaptability,so that they cannot be used to implement the absolute gravity measurement.Thus,the application areas of atomic gravimeter are greatly limited.In this paper,we integrate a system of absolute gravity measurement on a truck based on a compact homemade atomic gravimeter.This atomic gravimeter has a small size,light weight,low power consumption,and its accuracy is estimated as 10μGal in the case of laboratory environment.This system consists of atomic gravimeter for gravity measurement,passive isolation platform for vibration suppression,posture platform for tilt adjustment,differential GPS for altitude measurement,UPS for power supply,air-conditioned truck for temperature control and transportation.At first,we estimate the performance of environmental adaptability for this measurement system on the truck,and it is found that this system can still work even at a high field temperature of 40℃ and a big tilt angle of 8°for the road.Besides,the experimental procedures of absolute gravity measurement and the methods of processing measured data are introduced.The Coriolis effect is analyzed and the dependence of measured gravity on the orientation of the truck has been measured.Finally,the repeated line measurements are performed on a flat field road.The accuracy of self-coincidence for absolute gravity measurement is evaluated to be 30μGal and the difference in measured gravity among different locations is about 3080μGal.Besides,we obtain the vertical gravity gradient of the earth by measuring the absolute gravity values at different altitude sites on a slope road,and the value is estimated to be-231(36)μGal/m.The presented results can provide the basic reference for the field absolute gravity survey.