Frequency Analysis and Filtering Processing of Gravity Gradient Data from GOCE

Abstract

AbstractThe removal of low‐frequency errors is an important task in Gravity field and steady‐state Ocean Circulation Explorer (GOCE) data processing, which suffers from a large number of errors. This paper analyzes the frequency characteristics of gradient data in the time domain and then derives a formula that can represent the relationship between degree and frequency. Moreover, two primary filtering strategies, namely the remove‐restore method and the forward‐backward filtering technique, are presented. The former can solve low‐frequency signal loss during filtering, while the latter can resolve the phase‐drift problem. The final result shows that the proposed formula can accurately show the relationship between the maximum cut‐off frequency and degree of the spherical harmonic model. The proposed filtering method is proved to be effective in removing low‐frequency errors while saving signals in the measurement bandwidth.