Precise estimation of PCV and its influence on POD for COSMIC-2

To ensure that ensure the normal operation of the Constellation Observing System for Meteorology, Ionosphere and Climate-2 (COSMIC-2) satellite mission, it is crucial to perform precise orbit determination (POD) using the onboard GPS data. This study aims to enhance the accuracy of POD by performing an in-flight correction of the phase center variation (PCV) for the GPS receiver antenna on the COSMIC-2 satellite. Using the simplified dynamics method to perform orbit determination for COSMIC-2 satellites, we estimate the PCV model using both the direct approach and residual approach, and evaluate the orbit determination results through internal and external consistency assessments. The results show that the root mean square (RMS) value of overlapping orbit comparisons accuracy without considering PCV correction is at the centimeter level, while the RMS value of the reference orbit comparison accuracy is at the decimeter level. With the PCV model corrections approximated by the direct approach and residual approach, 3D RMS values experience a reduction of 2.5mm and 1.3mm, respectively, based on 4-hour overlap orbit comparison.