STUDIES ON A METHOD FOR DETERMINING THE PRECISE GRAVIMETER PHASE LAG

Since the 1980s, global earth models based on seisndc and free oscillation datahave predict 0°-0.02° phase lag corresponding to about 0- 2 s time lag for tidalwaves at the earth's surface' In principle, phases from earth tide observations couldhelp to verify the global earth models or to constrain the adustment of these modelsif the phases of earth tide observations corrected would be accurate to much betterthan 0'02 ° . For this purpose, it is important to deterndne the phase lag of the pre-cise gravimeter' ACCording to system identification principle, a method fordeterndning the phase lag of the precise gravimeter is given in this paPer' As anexample, the method was used to detendne the phases lag of the ET-2l and it wasshown that the phases lag angle t0 be relative to l5 main tidal waves individually'