Performance Analysis of BeiDou-3 Common-View Time Transferring.

Abstract

Firstly, four types of BeiDou dual-frequency combined common-view time transferring modes were briefly introduced. The software rnx2cgg, supporting the new signals in BeiDou-3 not included in CGGTTS V2E (Common GNSS (Global Navigation Satellite System) Generic Time Transfer Standard Version 2 Extended), was developed for converting RINEX (Receiver Independent Exchange Format) to CGGTTS. Secondly, the BeiDou timing error models were comprehensively analyzed, including SISRE (Signal-In-Space Ranging Error), pseudorange measurement noise, and DCB (Differential Code Bias). Then, the common-view weighting function was mathematically determined based on the error modes. Finally, the performances of single-station timing and between-station common-view were analyzed with the time transfer experiments between BSNC (Beijing Satellite Navigation Center) and MGEX (The Multi-GNSS Experiment and Pilot Project) stations. The experiments show that, the closure error of the whole link from ground to space is better than 2 ns. The BeiDou common-view noise is about 0.7 ns, corresponding to the time transferring stability of $1\times {10}^{-9}/\tau$ in short and medium term over long distance.