Estimation of antenna phase center offsets for BDS-3 satellites with the metadata and receiver antenna calibrations

Accurate satellite phase center offsets (PCOs) are essential for GNSS data processing, and their calibration before launch and estimation in orbit have been crucial tasks since decades. However, for the third-generation BeiDou navigation satellite system (BDS-3), the results in most recent studies are derived from precise orbit determination (POD) by wholly or partly employing GPS L1/L2 antenna calibrations for receivers and the adjustable box-wing model for solar radiation pressure (SRP) modeling. Since the strategy usages are different, the estimated BDS-3 PCOs are also varied from studies. With the help of BDS-3 satellite metadata and the receiver antenna calibration of BDS signals, this study estimated BDS-3 satellite PCOs in orbit with long-term data. The results show that the X-offset estimated using the empirical SRP model with the BDS-3 metadata is the most stable. Further analyses of PCO estimation using GPS and BDS receiver antenna calibrations for BDS signals show that the Z-offset is strongly affected by the receiver antenna calibration model types. The correlation can be approximately determined by giving a change to receiver antenna calibration and expressed as: A network averaged bias in the Up-direction of receiver antenna results in a − 22.7 times change of MEO Z-offset for single BDS-3 POD as well as − 28.6 for the joint processing with GPS. This is consistent with the result derived from other studies although different method was applied. Therefore, receiver antenna calibrations need to be carried out precisely. Validation experiments are carried out for comparison between the manufacture and the newly SHAPCO models. Compared with the manufacture model, the average improvement of the root mean square of the overlapping orbit differences is close to 3%. Additionally, the experimental station coordinates by static PPP achieve improvements at the rate of 5% and 14% for B1I/B3I and B1C/B2a, respectively.