Effects of Different Antenna Phase Center Models on GPS-Derived Reference Frames

Abstract

In GPS week 1400, the International GNSS Service (IGS) switched from a relative antenna phase center model (APCM) for receiver antennas only to an absolute model including receiver and satellite antenna corrections. At the same time the International Terrestrial Reference Frame 2005 (ITRF2005) was adopted. These changes had a significant influence on the terrestrial reference frame (TRF). In order to study the influence of different APCMs on GPS-derived TRFs, four TRF solutions have been computed from 11 years of homogeneously reprocessed GPS data. The processing strategy for the four solutions is completely identical except for the APCM applied. The following models have been used: (1) the relative model IGS01 used by the IGS till GPS week 1400, (2) the new absolute IGS model IGS05 including radome calibrations, (3) IGS05 ignoring the radome calibrations for the receiver antennas, and (4) IGS05 including azimuth-dependent satellite antenna phase center variations (PCVs). Station coordinates and velocities have been estimated simultaneously with daily pole coordinates. Consistent time series of station coordinates have been generated using the corresponding reference frames for datum definition. This paper compares the station coordinates and velocities as well as the station coordinate time series arising from the four different reference frames.