中国空间站微波链路引力红移检验仿真实验

Simulation Test of Gravitational Redshift by Microwave Links of China Space Station

利用高精度空载/星载原子钟进行引力红移检验是物理学领域的研究热点。随着原子钟精度的不断提高,利用高精度时频信号检验引力红移和测定重力位成为可能。中国空间站二号实验舱预计于2022年10月在轨运行,并搭载高精度原子钟组,为高精度引力红移实验奠定了基础。利用中国空间站的一组上行微波链路与下行微波链路进行双向时间/频率比对,从而实现引力红移检验。由于两条链路的频率及路径相同且极化方向相反,可以极大地消除误差干扰。结果表明,当空间站搭载的原子钟稳定度为2×10^(-13)/√τ且长期稳定度约为10^(-18)量级时,引力红移检验精度可达到10量级,比目前国际上最高的引力红移检验精度高1~2个量级。

Objectives:Gravitational redshift test using high precision space-borne/sattelite-payload atomic clocks is always a hot topic in physics.With the improvement of the accuracy of atomic clocks,it is possible to use high-precision time-frequency signals to test the gravitational redshift and determine the gravitational potential.Methods:The experiment module of China space station(CSS)is expected in orbit in October 2022,which lays a foundation for high-precision gravitational redshift experiment.The dual-frequency combination method is applied to eliminate the propagation frequency shifts by using an uplink and a down‐link with the same frequency and different polarization direction.The gravitational redshift simulation experiment is carried out by using the microwave links of CSS time-frequency comparison system.Results:The results show that the stability of atomic clock achieves 2×10^(-13)/√τ,the long term stability reaches 10^(-18),and the accuracy of gravitational redshift reaches 10.Conclusions:It is 1-2 orders of magnitude higher than the highest accuracy of gravitational redshift in the world.