Analysis of the impact of large ring laser gyroscope (RLG) stationary noise on universal time (UT1) resolution

Universal Time (UT1) is a critical conversion parameter between the terrestrial and celestial reference systems, with important applications in satellite navigation, deep-space exploration, and related fields. Large ring laser gyroscopes (RLGs) can compensate for the lack of real-time UT1 data in space-geodetic methods. However, the current UT1 measurement accuracy of large RLGs is still limited by instrument noise, particularly noise in the high-frequency band. Using a parametric stationary stochastic-noise model fitted to published amplitude spectral density data for the G-ring, this study evaluates the effects of low-frequency power-law noise and high-frequency approximately white noise on UT1 measurement uncertainty. The relative trends among the noise scenarios remain consistent across 100 paired random-phase Monte Carlo realizations. Within the investigated range, the day-equivalent UT1 uncertainty is substantially more sensitive to changes in the high-frequency noise level than to the tested changes in the low-frequency component. Reducing the high-frequency noise level from approximately 2×10^-11 to 1×10^-12 rad·s^-1·Hz^-1/2 yields a day-equivalent UT1 uncertainty of approximately 0.096 ms at τ=10³ s, indicating the potential of large RLGs to provide short-term UT1 updates in real time.