Research On Methods Of Regional Gravity Field Reconstruction

In recent years,there's an increasing need in exploring gravimetry data reconstruction methods withhigher accuracy and higher resolution.Because of the high cost of gravimetry,the cost of the way to get high accuracy gravimetry data through measure more serried gridding will be very huge.During the process of gravimetry,due to the factors,for example,the unstability of the measure equipment,gravimetry data will become seriously irregular and incomplete,which means it is necessary to reconstruct the incomplete gravity data to get the complete data to improve the quality of the gravity information.Under the background of earth gravimetry and earth gravity field modeling,this paper did researches on gravity anomaly data reconstruction based on remove-restore technique.The main work of the paper are as follow:The important basic concepts in gravity field theory are summarized,and the origin and meaning of related concepts were introduce.Basic formulas in the gravity field theory were derived?And the spheric harmonic expansion of gravitational potential and anomalous potential were given.The principles of different interpolation fitting methods were studied,and the indexes about the accuracy of data reconstruction was confirmed.Gravity disturbance data was calculated by using EGM2008 model.With this model data,simulation experiments were done to compare the adaptability of the different interpolation methods.Results show that cubic spline interpolation method performs the best when no noise was introduced,while piecewise linear interpolation will be the best when noise was imported.The principles of remove-restore technique were analyzed in detail.And the three main processes,remove,conversion and restore,of the technique were analyzed amply,including their contents and implementation methods.Withthe spectrum characteristics of gravity anomaly data,it indicates that remove-restore technique is applicable in this field.EGM2008 model data wasapproximatelycorresponding to the marine gravity anomaly data.Results shows that such correspondence will import error with mean as 1.5745×10-3mGal,which can be ignored.Combined with three interpolation fitting methods,remove-restore technique was used to reconstruct the marine gravity anomaly data.Comparison of this process with another reconstruction method which just uses interpolation fitting directly without remove-restore technique indicates that with same interpolation fitting methods,using remove-restore technique will obtain better results than the latter.Besides,the suitability of these different interpolation fitting methods were analyzed and compared.Results shows that cubic spline interpolation method performs the best,piecewise cubic Hermite method is the second,and piecewise linear interpolation is the third.