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Abstract:
The optical clock has achieved rapid development in the past two decades, demonstrating excellent stability and uncertainty. The optical clock can measure the gravitational potential difference between two different sites via frequency comparison, which provides a novel possibility for the measurement key payload of next generation satellite gravimetry missions. Therefore, a closed-loop simulation is carried out in this study to evaluate the ability of the satellite-based optical clock to retrieve the time-variable gravity signals. In order to truly reflect the measurement characteristics of the optical clock, the mechanism of power law noise generated by the optical clock is analyzed during the simulation, and a noise time series is generated. And two gravimetry modes by the optical clock are set up to explore the application scenarios of the satellite-based optical clock: one mode is the single satellite space-to-ground mode in which the ground-based optical clocks are measured by the satellite-based optical clock, and the other mode is the dual satellite space-to-space mode in which the measurement is performed between the satellite-based optical clock and the satellite-based optical clock. In addition, time-variable signals are considered in the simulation process, and the results based on the least-squares adjustment are analyzed and discussed. The simulation results demonstrate that: (1) The optical clock is extraordinarily sensitive to the low-frequency signals of the gravity field. (2) The space-to-ground mode has better ability to retrieve time-variable signals than the space-to-space mode. (3) It is feasible to use the satellite-based optical clocks to retrieve the temporal gravity field.
