Calibration of the Accelerometers Onboard GRACE with the Dynamic Method

A dynamic method for the calibration of the GRACE accelerometers was the focus of this study. The calibration parameters of the accelerometers was estimated using an integrated adjustment combining the precise orbit (PO), K-band range rate (kRR), and the earth gravity model (EGM). The scales and the time series of the biases were derived; the accumulated geoid error of the recovered EGM is 4cm till 100 degrees, which is superior to that from the monthly EGM derived by center for space research (CSR) at the same spatial resolution. These results were used as a reference to check the strategy for calibrating the accelerometer with a fixed EGM background. It was found that the magnitude of the differences was on the order of 10(-8) m (middle dot) s(-2) for the non-conservative forces derived from the calibration parameters. Thus, it was concluded that the strategy for fixing the EGM cannot fully utilize the ability of the accelerometer. Our results provide a scientific basis for the further processing of satellite gravimetry data in a routine mode, and can also provide reliable non-conservative forces for interdisciplinary scientific research.