Research Progress on TWSTFT Mobile Calibration Station

To achieve more precision calibration between two any signal system' ground stations of two-way satellite time and frequency transfer (TWSTFT), a new TWSTFT calibration method is proposed based on two TWSTFT mobile stations to calibrate systematic error of time comparison between any two ground stations. Two TWSTFT mobile stations are developed. To measure the systemic error between the two mobile stations, a zero baseline comparison experiment is designed. The standard deviation of equipment delay of two mobile stations are respective 0.102, 0.038 ns. The standard deviation of systematic error of zero baseline comparison is 0.124 ns. To validate function of two mobile stations, a long baseline comparison experiment is designed between two ground stations at Tianjin and Lintong. The result is highly consistent with GPS Common-View comparison between two stations. To farther validate performance of two mobile stations, a long baseline comparison experiment be designed between two ground stations at Changchun and Lintong. The result is shown that the standard deviation of clock difference of two ground stations is 0.347 ns after moving the drift of cesium atomic clock at Changchun. The two TWSTFT mobile stations can implement calibration of systematic error of time comparison between any two ground stations.