MEMS (Micro electro mechanical system) gravimeter

Abstract

The invention discloses an MEMS (Micro electro mechanical system) gravimeter, which comprises oscillator units, a displacement sensing structure, a displacement detection circuit, a cavity body and a horizontal adjusting base, wherein the oscillator units are arranged inside the cavity body; each oscillator unit comprises a negative-stiffness spring, a positive-stiffness spring, a detection mass and an outer frame; the detection mass is connected with the outer frame through the positive-stiffness spring and the negative-stiffness spring; the positive-stiffness spring and the negative-stiffness spring are symmetrically arranged about the detection mass; the outer frame is fixedly connected with the cavity body; the displacement sensing structure is arranged on the surface of the detection mass; the displacement detection circuit is used for detecting displacement signals of the displacement sensing structure; the oscillator unit realizes reduction of eigenfrequency through match between the positive-stiffness spring and the negative-stiffness spring; and through detecting the displacement of the detection mass, changes of a gravitational acceleration are further detected. The MEMS gravimeter has the advantages that the stability is high; the size is small; the weight is light; the production cost can be effectively reduced; and the research and development difficulty of a signal detection unit and a stable platform can be effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of gravity measurement, and more specifically relates to a MEMS gravimeter. Background technique [0002] A gravimeter is an instrument for measuring the acceleration of gravity, which is of great significance in the fields of geophysics and underground resource exploration. At present, the gravimeter can be mainly divided into two categories: one is the absolute gravimeter, and the other is the relative gravimeter. The absolute gravimeter is represented by Micro-g&LaCoste's FG5-X, which measures the absolute gravitational acceleration by measuring the position and time relationship of objects falling in vacuum very accurately. Its precision is very high, the accuracy can reach 2μGal / √Hz, and the accuracy can reach 15μGal / √Hz (1Gal=1cm / s 2 ). But the whole instrument is also very huge, with a total weight of 150kg and a total volume of 1.5m 3 . Its price is very expensive, reaching several million yuan....

AI Technical Summary

Problems solved by technology

However, the measurement accuracy and stability of existing MEMS accelerometers still cannot meet the requirements of gravimeters.

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