Analysis Of Interferometric Imaging Radar Altimeter Errors On Accuracy Of Marine Gravity Field Inversion

Geodesy and other related geoscience disciplines often use geoid as the datum.The fluctuation and shape of geoid are related to the gravity field of the earth.Therefore,the fluctuation information of geoid can be used to invert the ocean gravity field.Satellite altimetry technology can obtain global sea surface height information.Many scholars have done a lot of work on inversion of ocean gravity field using satellite altimetry data.However,the traditional altimetry satellite can only measure one-dimensional altitude,and the congenital shortage of data structure limits the inversion of ocean gravity field by altimetry.The interferometric imaging radar altimeter carried by SWOT satellite and Tiangong-2 in China can measure the two-dimensional altitude of the sea surface,which will be beneficial to the study of the marine gravity field.In this paper,based on the traditional one-dimensional satellite altimetry method to retrieve the information of marine gravity field,the method to retrieve the information of marine gravity field from two-dimensional geoid height data and the influence of geometric model errors of interferometric altimetry on the accuracy of marine gravity field inversion are studied.The results show that the difference between the vertical deviation calculated by inversion of two-dimensional geoid height data and that calculated by EGM2008 model is about 0.15%.The difference between the total tensor of disturbance gravity gradient calculated by inversion of two-dimensional geoid height data and that calculated by EGM2008 model is less than 0.6% on the diagonal of the total tensor,while the difference between the three elements calculated by non-diagonal three-dimensional geoid height data is less than 0.6%.The difference of each element is about 3%.The systematic errors of geometric model parameters of interferometric altimetry have little influence on the relative elevation of geoid and the accuracy of vertical deviation calculation.The random errors of geometric model parameters of interferometric altimetry have great influence on the inversion calculation of gravity field.The above results can provide reference for the design of interferometric altimetry system and the selection of inversion methods of ocean gravity field.