Gravity potential determination based on China Space Station Dual-frequency microwave links frequency transfer

TL;DR

This paper develops a high-precision model for determining gravity potential using dual-frequency microwave links from the China Space Station, achieving centimeter-level accuracy in simulated experiments.

Contribution

It introduces a novel gravity potential determination model based on space station frequency transfer, considering multiple effects up to c^{-4} and applicable for high-precision measurements.

Findings

Achieved gravity potential accuracy of about 1 m^2/s^2 in simulations.

Model suitable for measurements at the 10^{-19} frequency shift level.

Enables centimeter-level gravity potential difference measurements with optical atomic clocks.

Abstract

The China Space Station (CSS) is currently in orbit and carries the high-precision optical atomic clock with stability of approximately $2.0 \times 10^{-15} / \sqrt{\tau}$ in its experiment module. We have developed a model to determine the gravity potential (GP) based on the gravity frequency shift equation and have created both one-way and dual-frequency transfer models up to $c^{-4}$. These models consider effects from the troposphere, ionosphere, and solid Earth tides. The proposed model is suitable for measurements at the magnitude of $10^{-19}$. Based on the CSS mission, we conducted the simulation experiments. The results indicate that when processing the simulation frequency signal using the proposed model, we can obtain the GP with the accuracies of $ (1.13\pm0.71)\,\mathrm{m^2/s^2}$, $ (0.09\pm0.89)\,\mathrm{m^2/s^2}$, and $(0.66\pm1.18)\,\mathrm{m^2/s^2}$ for cutoff elevation angles of $5^{\circ}$, $10^{\circ}$ and $15^{\circ}$, respectively. With the high-precision optical atomic clock onboard the CSS, the proposed model enables us to measure the GP differences in the magnitude of centimeter-level accuracy.