Active TWSTFT via geostationary satellites mitigates common systematic errors, yet it is limited to specialized UTC(k) laboratories. This study seeks to broaden the access to UTC(k) signals to passive (Rx-only) users with non-specialized instruments like Software Defined Radio (SDR) receivers. Using an Orbit Determination (OD) filter, ranging measurements from active TWSTFT networks are processed to determine satellite ephemeris and station hardware delays, achieving ~1m residuals over 3 months. Corrections for dynamic path and atmospheric delays enable direct UTC(k) comparisons with passive users. Validation with the active network yields ~1 ns stability after 1 day of averaging. Future phases will focus on mobile station experimentation. Limitations include tropospheric calibration models at low elevation angles and uncertainties in station positions. Orbit-keeping maneuvers disrupt OD the solution coherence and service continuity; ongoing efforts strive to estimate ∆𝑉 for real-time passive TWSTFT implementation.
Track ID:
5
Track Name:
Timekeeping, T&F Transfer, Telecom and GNSS Applications
