BeiDou Time Transfer With the Standard CGGTTS

Area of Science:

• Geodesy and Geophysics
• Satellite Navigation Systems
• Metrology

Background:

• The Royal Observatory of Belgium developed R2CGGTTS software for precise clock solutions.
• The Common GNSS Generic Time Transfer Standard (CGGTTS) is a key technology in time transfer.
• The BeiDou Navigation Satellite System (BDS) offers global navigation capabilities.

Purpose of the Study:

• To extend the R2CGGTTS software for BeiDou Navigation Satellite System (BDS) compatibility.
• To evaluate the performance of BDS in common view (CV) time transfer.
• To compare BDS time transfer results with those from GPS and Galileo.

Main Methods:

• Upgrading the R2CGGTTS software to support BeiDou satellites in MEO, IGSO, and GEO orbits.
• Conducting common view (CV) time transfer experiments using BDS, GPS, and Galileo.
• Analyzing time transfer noise and biases in the obtained solutions.

Main Results:

• BeiDou Medium Earth Orbit (MEO) satellites introduce higher noise in time transfer compared to GPS, attributed to elevation-dependent code measurement delays.
• Biases, potentially in the nanosecond range, were observed between different BeiDou MEO satellites when using dissimilar receiver hardware.
• Incorporating BeiDou Inclined Geosynchronous Satellite Orbit (IGSO) and Geostationary Earth Orbit (GEO) satellites increases observation numbers but adds significant noise to CV results.

Conclusions:

• The R2CGGTTS software has been successfully extended to support the BeiDou Navigation Satellite System (BDS).
• BeiDou MEO satellites show potential for time transfer but require further investigation into code measurement biases and receiver-dependent effects.
• While IGSO and GEO satellites enhance data availability, particularly in the Asia-Pacific region, their current use introduces considerable noise into common view time transfer solutions.