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arXiv · 2508.19886

Relativistic formulation for dual one-way Doppler Cancellation Scheme observables for gravitational redshift tests

Cheng-Gang Qin·Tong Liu·Yang Li·Qi-Long Gong·Qin Li·Zhi-Yu Ma·Yu-Jie Tan·Cheng-Gang Shao
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Abstract

Gravitational redshift is a fundamental prediction of general relativity and a sensitive probe of possible deviations from it. Motivated by recent progress in optical clocks and satellite-ground frequency transfer, we study a dual one-way optical Doppler-cancellation observable for space-based gravitational-redshift tests. The corresponding observable is constructed by combining oppositely directed one-way frequency observables, namely an uplink and a downlink whose measurements are recorded at the receiving terminals and combined in post-processing. We derive the corresponding relativistic observable up to order $c^{-3}$, as required for future $10^{-18}$-level clock comparisons. The resulting combination suppresses the first-order Doppler contribution to second order while retaining the gravitational-redshift signal. We analyze the dominant residual effects, including higher-order Doppler terms, atmospheric delay, Shpiro delay, tidal effects, clock synchronization etc. The formalism is applied to representative satellite-ground configurations, including an ACES/CSS-like low-Earth-orbit configuration and a geostationary Earth-orbit satellite. The results show that the dual one-way optical DCS configuration provides a useful relativistic framework and error-modeling reference for future $10^{-18}$-level space-based gravitational-redshift tests, while highlighting the need for stringent clock synchronization.

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Cheng-Gang Qin, Tong Liu, Yang Li, Qi-Long Gong, Qin Li, Zhi-Yu Ma, Yu-Jie Tan, Cheng-Gang Shao. 2025-08-27. Relativistic formulation for dual one-way Doppler Cancellation Scheme observables for gravitational redshift tests. https://arxiv.org/abs/2508.19886

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