Empirical Detection of a Finite Temporal Correlation Scale in GNSS Satellite and Ground Atomic Clock Time Series

Time is usually treated as a passive parameter in physical theories, yet whether it possesses intrinsic dynamical structure remains largely unexplored from observational data. Here we analyze long-term atomic clock time series from Global Navigation Satellite Systems (GNSS), including multiple orbital classes, together with independent ground-based atomic clock comparisons provided by the National Institute of Information and Communications Technology (NICT). Using autocorrelation analysis combined with block-shuffle surrogate testing, we identify a statistically significant and robust temporal correlation peak at a delay of approximately 30–35 minutes in GNSS satellite clocks. Remarkably, this characteristic timescale is independent of orbital altitude, satellite system, and gravitational environment, and is absent in ground-based clocks operating under static conditions. We further demonstrate consistency of this timescale across time-domain and frequencydomain analyses, ruling out preprocessing artifacts and input-driven effects. These results provide empirical evidence that physical clock dynamics retain a finite temporal memory, motivating the concept of a universal temporal inertia scale.