Estimation of antenna phase center offsets for BeiDou IGSO and MEO satellites

摘要

Based on a global GNSS tracking network, the B1I/B3I ionospheric-free phase center offsets (PCOs) are estimated for BeiDou Inclined Geosynchronous Orbit (IGSO) and Medium Earth Orbit (MEO) satellites. Peak-to-peak variations of up to several decimeters or even meters that depend on the solar radiation pressure (SRP) model and the sun elevation angle above the orbital plane (beta angle) are found in the dailyx-offset estimates. Different SRP modeling has a negligible effect on they-offset estimation, but the scatter ofy-offset estimates depends on the beta angle. Thez-offset estimates do neither exhibit a dependence on the SRP model nor the beta angle, but they have a larger scatter thanx-offset andy-offset estimates. By comparing the performance of different SRP models in the estimation of BeiDou PCOs, the SRP models suitable for the estimation of BeiDou-2 and BeiDou-3 PCOs are determined to solve final PCOs. The BeiDou satellite PCO estimates are compared with the model values currently used within the International GNSS Service, the manufacturer values published by the Test and Assessment Research Center of China Satellite Navigation Office, and a set of BeiDou-3 MEO PCO estimates previously reported by the Chang'an University. Finally, it is demonstrated that the orbit quality of BeiDou IGSO/MEOs and the accuracy of station coordinates obtained from BeiDou-only precise point positioning benefit from the newly estimated BeiDou PCO model.