Performaces and telemetres analysis of BD satellite passive hydrogen maser

An atomic clock is one of the most important payloads in navigation satellites. It is in charge of generating and maintaining the satellite time. The performance and on-orbit adaptability of a 23-kg passive hydrogen maser (PHM) have been verified using the experimental satellite of the third-generation Beidou satellite navigation system (BDS-3). The clock offset of the PHM is less than 1 ns per day. In BDS-3, PHMs operate as the master clocks in the GEO, IGSO, and MEO satellites; therefore, they are important in the system operation. Herein, we present the design and performance evaluation of the PHM and compare the hydrogen maser, rubidium atomic clock, and cesium atomic clock. Using the satellite-ground time-difference data, we analyze the frequency stability and time prediction accuracy. Furthermore, we perform a preliminary analysis of the operating status and aging trend based on the satellite telemetry data.