Method and system for extracting vertical gravity gradient based on absolute gravimeter

Abstract

The invention provides a vertical gravity gradient extraction and system based on an absolute gravimeter. The method comprises the steps that the vertical gravity gradient of all observation data of a repeated freely-falling body is calculated, a falling distance fitting residual sequence of the each-time freely-falling body is calculated, and superposition is carried out to solve an average, and a residual mean value sequence is obtained; modeling is carried out based on the residual mean value sequence to obtain a system error model; a residual sequence of the system error model is calculated, and falling time frames participating in calculating are determined; for the whole falling time frame of the each-time freely-falling object, the falling distance observation quantity is corrected, and the vertical gravity gradient is calculated again; the vertical gravity gradient is calculated by means of corrected falling distance observation quantity within the falling time frame; statistics is carried out on repeated freely-falling body calculation results, and the vertical gravity gradient optimal estimation value and statistics precision are obtained. The absolute gravity measurement cost is reduced, and meanwhile it is ensured that the measured vertical gravity gradient result is stable and effective.

Description

technical field [0001] The invention relates to a method for determining a high-precision vertical gravity gradient, in particular to a method and a system for determining a vertical gravity gradient using observation data of a free-falling absolute gravimeter. Background technique [0002] For a long time, when using a free-falling absolute gravimeter for absolute gravity measurements, it is necessary to use a high-precision relative gravimeter to determine the vertical gravity gradient [1-3] . In fact, the observation data of the free-falling absolute gravimeter, that is, the falling time-distance sequence of the free-falling motion, contains the information of the vertical gravity gradient. If the absolute gravity measurement data can be used to determine the vertical gravity gradient, on the one hand, the workload and necessary equipment for absolute gravity measurement can be reduced; on the other hand, the vertical gravity gradient determined independently can be used...

AI Technical Summary

Problems solved by technology

However, when R.G. Hipkin calculated the vertical gravity gradient, he did not detect and eliminate the possible systematic errors in the observation data, nor did he give the basis for the selection of the falling period of the free fall movement. So far, the absolute gravity measurement data has been used to calculate the vertical gravity Gradient is still in the experimental stage, and has not formed a stable and effective data processing method

[0005] Although many scholars have studied the method of modeling the errors contained in the FG5 observation data, their focus has been on determining the absolute gravity acceleration results with higher accuracy and reliability, without further research on the determination of the vertical gravity gradient method

Although R.G.Hipkin (1999) obtained good results in the study of determining the vertical gravity gradient, he did not take into account the influence of factors such as system error and time period selection. When another set of FG5 observation data is replaced for processing, the results will have obvious deviations , so it is not universal and cannot form a stable and effective data processing method

Therefore, there has not been a stable and effective method to determine the vertical gravity gradient using the observation data of a free-falling absolute gravimeter.

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