Estimating BDS-3 Satellite Differential Code Biases with the Single-Frequency Uncombined PPP Model

Area of Science:

• Geodesy and Geophysics
• Satellite Navigation Systems
• Atmospheric Science

Background:

• Differential Code Bias (DCB) is a significant systematic error affecting satellite positioning and ionospheric modeling.
• Accurate estimation of DCBs is crucial for enhancing the performance of Global Navigation Satellite Systems (GNSS).

Purpose of the Study:

• To estimate BeiDou-3 global navigation satellite system (BDS-3) satellite DCBs using a single-frequency (SF) uncombined Precise Point Positioning (PPP) model.
• To investigate the impact of station latitude on the accuracy of satellite DCB estimation.

Main Methods:

• Utilized BDS-3 B1 observations from 25 International GNSS Service (IGS) stations globally in March 2023.
• Employed the single-frequency uncombined Precise Point Positioning (PPP) model for DCB estimation.
• Analyzed the latitude dependence and hemispheric differences in DCB estimation accuracy.

Main Results:

• Satellite DCB estimation accuracy exhibits significant latitude dependence, with greater variability in low-latitude regions.
• Mid- to high-latitude stations demonstrate more consistent and stable root mean square (RMS) values for satellite DCBs.
• Excluding low-latitude stations and using data from 17 mid- to high-latitude stations reduced the RMS of absolute offsets to below 0.63 ns.

Conclusions:

• The accuracy of BDS-3 satellite DCB estimation is influenced by geographical latitude and ionospheric variability.
• Incorporating a sufficient number of mid- and high-latitude stations is essential for reliable DCB estimation using SF observations.
• This study highlights the importance of station distribution in mitigating ionospheric effects for precise satellite navigation.