The test of gravitational redshift (GRS) is one of the important experiments used to verify the Einstein equivalence principle (EEP) in general relativity (GR). The China Space Station (CSS) is equipped with a high-precision Sr atomic clock for future GR tests. We simulate an experiment to test GRS by comparing phase signals from the CSS and the Beijing Miyun ground station. We simulate the signal transmission via laser link combinations, obtain the gravitational redshift from the EGM2008 model, and apply a least-squares estimator to three days of simulated data. Under conservative error assumptions, we obtain a constraint on the GRS violation parameter of $\alpha =(0.14\pm 4.65)\times {10}^{-7}$. The geopotential model error and the accumulated clock phase noise are identified as the dominant error source, and it has been demonstrated that testing with phase signals is not affected by signal discontinuities.

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• Atomic, optical & lattice clocks
• Experimental studies of gravity
• General relativity
• Gravitation