Differential Code Bias Estimation using Multi-GNSS Observations and Global Ionosphere Maps

Abstract

Measurements of Global Navigation Satellite System (GNSS) receivers are affected by systematic offsets related to group and phase delays of the signal generation and processing chain. The resulting code and phase biases depend on the transmission frequency and the employed signal modulation. Within this study differential code biases (DCBs) of legacy and modernized GNSS signals are derived from pseudodrange observations of a global multi-GNSS receiver network. Global ionosphere maps (GIMs) are employed for the correction of ionospheric path delays. Based on six months of data collected within the Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS), DCBs for the publicly available signals of GPS, Galileo, and BeiDou have been determined. The quality of the resulting DCB estimates is assessed and compared against group delay parameters transmitted by the GNSS providers as part of the broadcast ephemeris data.