Estimation and Validation of the IGS Absolute Antenna Phase Center Variations

To validate the IGS proposed absolute antenna phase center variations (APCVs) and offsets for the GPS satellites, an independent APCV model is derived with the EPOS software using data of 90 IGS stations for the days 292 to 326 in 2003. The estimated block-type-specific models agree with the IGS ones within 1 mm rms for the APCVs and about 10 cm in the offsets. However, we found significant differences up to 0.8 m in the offsets among satellites belonging to the same block type. The APCVs for the individual satellite could be divided into 5 groups. Therefore, we suggest group-specific APCVs plus satellite-specific offset for IGS application. Furthermore, the same data set is also analyzed fixing the IGS proposed APCVs and offsets. Their impact is investigated by comparing the new results with those using the relative PCVs and offsets.