GPS Clock Products for NGS

In 2021, we designed a Kalman-filter algorithm to estimate GPS satellite clocks with high precision and accuracy, based on 20 ground stations equipped with hydrogen-maser atomic clocks [1]. From the perspective of operation, it is essential to process a large set of available stations to improve robustness. As a test, we have established a ground network composed of 18 hydrogen-maser stations and 32 quartz-oscillator stations. 30-day daily clock products for GPS satellites and ground stations, generated at a 30-second time interval, exhibit a good match with the International GNSS Service (IGS) final product, both in the long term and short term. This work paves the way for the routine publication of NGS clock products.