Combined use of single-frequency data and global ionosphere maps to estimate BDS and Galileo satellite differential code biases

Abstract

Differential code biases (DCBs) are the most significant systematic errors in global navigation satellite system (GNSS) ionospheric total electronic content (TEC) monitoring and other code-related applications. Currently, the rapidly developing GNSS benefits from the Chinese BeiDou (BDS) and European Galileo systems that continuously offer position, navigation and timing services. In this way, the determination of satellite DCBs (SDCBs), which generally relies on GNSS data collected from dual- or multi-frequency geodetic-grade receivers, is of great importance, especially for the BDS and Galileo systems. However, the use of these geodetic-grade receivers implies a substantial increase in hardware costs. In this paper, we propose a single-frequency (SF) method for the determination of the BDS (C2I–C7I) and Galileo (C1X–C5X) satellite DCBs with the combined use of global ionospheric maps (GIMs) and low-cost SF multi-GNSS receivers, thereby greatly reducing the hardware costs. The mean precision of the satellite DCBs estimated from multi-GNSS data of a standalone SF receiver is approximately 0.35 ns for Galileo and 0.51 ns for BDS, when taking the DCB products published by the Deutsches zentrum für Luft-und Raumfahrt (DLR) as ground truth.