Determination of multi-GNSS differential code biases with satellite antenna phase center corrections

The determination of multi-GNSS Differential Code Biases (DCBs) is crucial for improving both precise positioning and ionospheric modeling. While frequency-specific antenna phase center (APC) information for multi-GNSS is available, the IGS Analysis Centers have not yet fully incorporated APC calibrations into their DCB products. This study evaluates the effect of Antenna Phase Center (APC) corrections, specifically satellite Phase Center Offset (PCO) corrections, on multi-GNSS DCB estimation. Two correction strategies are proposed: (1) a rigorous approach applied during DCB estimation, and (2) an approximate approach that adjusts existing DCB products using z-PCO corrections. Through a six-month analysis, i.e., July–December 2022, we show that PCO-corrected DCB products exhibit high consistency, with root mean square differences of less than 0.1 ns compared to DLR's PCO-corrected DCB products. Positioning tests with 20 MGEX stations demonstrate notable accuracy improvements for SF-PPP when applying PCO-corrected DCBs, including a 20.3% increase for GPS and a 13.1% improvement for BDS-3. SFIC-PPP results further show convergence time reductions of 54.9% for GPS and 10.7% for BDS-3. Since June 2022, the newly generated CAS PCO-corrected DCB products have been routinely provided to the International GNSS Service (IGS).