Full-tensor gravity gradient measurement device and method

Abstract

The present invention relates to a full-tensor gravity gradient measurement device and method. The full-tensor gravity gradient measurement device comprises a computer, a cube frame and accelerometers which are arranged at the eight corners of the cube frame respectively and of which the sensitive shafts are in the horizontal planes. For the four accelerometers in the same horizontal plane of the cube frame, the sensitive shafts of one to three accelerometers are along a west-east direction, and the sensitive shafts of the other accelerometers are along a south-north direction. For the accelerometers which are located in the different horizontal planes of the cube frame and of which the sensitive shaft directions are same, only two accelerometers are in the right above direction and the right below direction, and the above devices are put in a right angle coordinate system, so that the edges of the cube frame are along the X, Y and Z directions separately, and the XX, YY, XY, XZ and YZ components of the gravity gradient and the other components are calculated by the reading of the accelerometers. The measurement device and method of the present invention can realize the gravity gradient measurement at the normal temperature and at the static state that the accelerometers do no need to rotate, can work in an near earth space, and also can be used in a micro-gravity environment.

Description

technical field [0001] The invention relates to the measurement of the earth's gravity field, in particular to a full tensor gravity gradient measurement device and a measurement method. Background technique [0002] Accurate measurement of the earth's gravity field can invert and estimate the distribution and changes of substances, and has important application prospects in basic geological research, regional gravity surveys, geodesy, exploration of oil and gas fields and solid mineral resources, and gravity-assisted navigation. The gravity gradient of the earth reflects the rate of change of gravity along different directions in space. The gravity gradient at any point is described by a tensor, and the size of the tensor is the gravitational acceleration g of the position i The first derivative of (i=x,y,z) with respect to the space, that is [0003] Γ = ∂ ...

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Problems solved by technology

However, under the gravitational environment of 1g on the ground surface, to realize the vertical component Γ of the gravity gradient ZZ The measurement of the accelerometer puts forward extremely high requirements. For example, if the baseline length of the two accelerometers in the vertical direction is 0.1m, if the requirement for Γ ZZ The measurement resolution reaches 1E (1E=10 -9 / s 2 ), the resolution of a single accelerometer is required to be better than 10 -11 g (g is the acceleration of gravity on the surface, 1g≈9.8m / s 2 ); On the other hand, if the accelerometer can work normally under the surface environment of 1g, its measurement range must be greater than 1g, that is to say, the accelerometer must have a dynamic range of 11 orders of magnitude, which is almost impossible to achieve

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