Estimation of TTL coupling coefficients for the GRACE-FO satellite laser ranging system based on the center of mass calibration maneuver signals
The Laser Ranging Interferometer(LRI)carried by the GRACE-FO satellite enables nanometer-level precision measurement of intersatellite range.The low-frequency component of LRI ranging errors is primarily attributed to TTL coupling noise.TTL coupling noise arises from the coupling effects of satellite attitude variations with offset of the Center of Mass(CoM)and Vertex Points(VP)of the Triple Mirror Assembly.In this study,a linear estimation model is adopted.By utilizing the maneuver signal data of the satellite during the CoM calibration phase and employing integrated and independent parameter estimation strategies based on sub-maneuvers in different directions,reasonable TTL coupling coefficients are obtained.The results indicate that the TTL coupling coefficients meet the design specification requirement of 200 um·rad-1.Furthermore,by converting TTL coupling coefficients into VP-CoM offset,indirect estimation of satellite CoM-offset is achieved.The obtained offset sequence aligns well with the results based on accelerometer measurements(the offset between satellite CoM and the accelerometer test mass,ACC-CoM offset),demonstrating that this method can serve as a supplementary approach for estimating the CoM-offset of GRACE-FO satellite.
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维普
