Method and system for measuring absolute gravity of freely falling body based on double interferometers

A technology of free fall and gravity measurement, applied in the direction of measuring device, gravitational field measurement, geophysical measurement, etc., can solve the problems of repeated measurement, adjustment, coincidence, and difficult elimination

Active Publication Date: 2014-12-10
NAT INST OF METROLOGY CHINA
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Problems solved by technology

[0005] In addition, high-precision gravity measurement will also be affected by yaw (rotation of the falling body around its own center of mass during the fall process), this phenomenon is because the optical center of the movable prism in the interferometer that is in free fall cannot match the center of mass of the falling body Completely coincident, so the fall will deflect during the fall
This effect is not easily eliminated and is time-dependent, with progressively worsening wear between the falling body and the pallet, introducing systematic errors in the measurement
Usually, the processing method is used to make repeated adjustments so that the optical center of the reflecting prism in the falling body coincides with the center of mass of the falling body as much as possible to reduce the influence of deflection, but this requires high processing methods, and repeated measurements and adjustments are required to process properly. falling body

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  • Method and system for measuring absolute gravity of freely falling body based on double interferometers
  • Method and system for measuring absolute gravity of freely falling body based on double interferometers
  • Method and system for measuring absolute gravity of freely falling body based on double interferometers

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Embodiment 1

[0043] Such as image 3 Shown is the principle diagram of the free-fall absolute gravity measurement system based on the double interferometer of the present invention, and this embodiment can be combined with image 3 Be explained.

[0044] The free-fall absolute gravity measurement system based on double interferometers is provided with up-and-down symmetrical interferometers. The interferometers include fixed prisms, movable prisms and beam splitters. The interferometers are irradiated by the same frequency laser light sources to interfere respectively; The first and lower movable prisms are arranged in the same falling body, the optical centers of the upper and lower movable prisms are separated by a predetermined distance, and the center of mass of the falling body is located between the two optical centers in the vertical direction.

[0045] Further, the distance between the optical centers of the upper and lower movable prisms is ≤5mm.

[0046] Further, the measuremen...

Embodiment 2

[0049] Using the free-fall absolute gravity measurement method carried out by the above-mentioned measurement system, the system is measured under the condition of vibration isolation or vibration compensation method, or the results of multiple measurements are averaged to eliminate the influence of random ground vibration disturbance; The laser of the same frequency is used to irradiate the upper and lower interferometers at the same time to generate interference respectively, and the data processing of the interfering light signals is carried out to obtain the gravity value g of a single drop. 上 and g 下 , perform multiple drop measurements and calculate the average and The distance ratio between the optical center of the upper and lower movable prisms and the center of mass of the falling body is fitted by using the results of multiple measurements of the same measurement point with the double interferometer; according to the gravity value g of a single drop 上 and g 下 A...

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Abstract

The invention provides a system for measuring absolute gravity of a freely falling body based on double interferometers. The system is provided with the interferometers which are symmetrical up and down; each interferometer comprises a fixed prism, a movable prism and a beam splitter; the interferometers are exposed to the irradiation of a laser light source of the same frequency to generate interference, respectively; the upper and lower movable prisms are arranged in the same falling body; optic centers of the upper and lower movable prisms are separated by a predetermined distance; the center of mass of the falling body is located between the two optic centers in the vertical direction. The system for measuring the absolute gravity of the freely falling body based on double interferometers is capable of eliminating the influence of deflection of the falling body on the measurement accuracy of the absolute gravity of the freely falling body. The invention also provides a method for measuring the absolute gravity of the freely falling body based on double interferometers.

Description

technical field [0001] The invention relates to a free-fall absolute gravity measurement method based on double interferometers, and also relates to a free-fall absolute gravity measurement system based on double interferometers, which belongs to the field of high-precision absolute gravity measurement. Background technique [0002] Accurate gravity value g is of great significance in the fields of geodesy, geophysics and precision metrology. At present, most countries in the world use the "free fall" method to measure absolute gravity. The measurement principle is to measure the time and distance experienced by the falling body in the process of free falling in the vertical direction in a high vacuum environment. According to Newton's second The law calculates the value of gravity g. [0003] The classic free-fall absolute gravity measurement system uses rubidium (or cesium) atomic frequency standard as the time measurement standard, uses high-stability laser as the length...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V7/14
Inventor 冯金扬
Owner NAT INST OF METROLOGY CHINA
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