Research On Reconstruction Algorithm Of Falling Body Trajectory For Laser Interferometer Absolute Gravimeter

High-precision absolute gravity measurement is of great significance in the fields of earth science,resource exploration,seismic monitoring,and missile guidance.Laser interferometer absolute gravimeter is a commonly used instrument for measuring the absolute value of high-precision gravitational acceleration.However,the current commercial absolute gravimeters are expensive and difficult to maintain.Therefore,research on high-precision absolute gravimeters has become an important topic.The laser interferometric absolute gravimeter uses a laser interferometric ranging system to measure the time and displacement of the falling body.The time reference is derived from the external high-stability rubidium atomic frequency standard,and the displacement reference is derived from the frequency-stabilized laser wavelength.Both can be directly traced to National time and length benchmarks,so the high-precision extraction of time and displacement coordinates in the free fall process of a falling body is the prerequisite for fitting and solving the gravitational acceleration.It directly affects the accuracy of calculating the value of gravitational acceleration.This article first introduces the composition structure of the laser interferometer absolute gravimeter,the calculation method of gravitational acceleration and the measurement principle of the interferometer.The algorithm of reconstructing falling body trajectory from laser interference signal data is studied,and the Hilbert transform method based on data continuation is proposed to suppress the Gibbs effect in the algorithm process.Finally,the simulation and actual measurement comparison experiments of the three algorithms are done,and the errors of the three algorithms to calculate the acceleration of gravity are analyzed.The experimental results show that the Hilbert transform method based on data continuation can not only suppress the Gibbs effect,but also improve The accuracy of gravity measurement.