Study On Precise Temporal Link Technology Of Gravity Acceleration Comparision Reference Value

Gravity acceleration is affected by time and space.Gravity measuring instruments are widely used in geodynamics research and national defense construction.The accuracy of their measurement results needs to be supported by absolute gravimeter comparison and gravity metrology system.Absolute gravimeter comparison can be traced directly to the international unit system,which is the fundamental guarantee for the accuracy of gravity measurement.The gravity comparison reference value is the gravity value of the point at a specified time.The gravity comparison and the traceability of the gravimeter will be affected by the time variable of gravity,thus introducing errors.Therefore,the establishment of time-link system is of great significance for the establishment and maintenance of gravity comparison points and the construction of domestic gravity metrology system.Taking the key comparison of global absolute gravimeters dominated by China in 2017 as an opportunity,this project aims to build a time-link system based on gravity comparison reference points,design a reasonable gravity time-varying monitoring system and gravity time-link method.The main research contents include:(1)The gravity time-varying monitoring system consisting of absolute gravimeter,relative gravimeter and comparison reference points.The characteristics are introduced in detail.The quality evaluation method of monitoring data is designed,including the calculation method of key parameters include instrument calibration factor,drift and noise level,data processing and system stability evaluation criteria,in order to realize continuous gravity time-varying observation and monitor system status.(2)Based on the long-term observation data of the international comparison points in 2017,the monitoring system is evaluated.The working status and noise of the superconducting and gPhone gravimeters and points are analyzed according to the results of key parameters.The quality of the continuous gravity observation data at the reference points is evaluated and the rationality of the system is verified.(3)Computing the corrected gravity residuals of reference points with the long-term observation results of relative gravimeter,designing the method of time link in the international comparison of absolute gravimeter and the traceability process of gravimeter,and analyzing the uncertainty of the corrected value of time link of superconducting gravimeter.