Summary of NIST GNSS and Satellite Time Transfer Article:
NIST uses two primary methods for high-precision clock comparison over long distances:
1. Two-way satellite time/frequency transfer (TWSTFT) via geostationary satellites
2. GNSS-based techniques using GPS and other satellite systems
GNSS methods don’t rely on the accuracy of on-board atomic clocks, only their availability. NIST uses both TWSTFT and GNSS techniques to distribute UTC(NIST) signals and contribute to International Atomic Time (TAI).
GNSS common-view is used in NIST’s remote calibration services and FMAS. TWSTFT, independent of GNSS, is now available as a remote calibration service.
The article emphasizes NIST’s use of both satellite-based methods for distributing precise time signals and contributing to international timekeeping standards.
Source: https://www.nist.gov/pml/time-and-frequency-division/time-services/gnss-and-satellite-time-transfer
Keywords: Atomic, Clocks, Signals, Metrology, Navigation
