Impact of Multi-GNSS Antenna-Receiver Calibrations in the Coordinate Domain

In order to obtain highly precise positions with Global Navigation Satellite Systems (GNSS), it is mandatory to take all error sources adequately into account. This includes phase center corrections (PCC), composed of a phase center offset (PCO) and corresponding azimuthal and elevation-dependent phase center variations (PCV). These corrections have to be applied to the observations since the pattern of the GNSS receiver antennas deviate from an ideal omnidirectional radiation pattern.
The Institut für Erdmessung (IfE) is one of the IGS accepted institutions for absolute antenna calibration. Recently, the operationally calibration procedure has been further developed to a post processing approach. Thus, PCC can also be estimated for all frequencies (including e.g. GPS L2C, L5) and systems like Galileo and Beidou. Additionally, the newly developed approach allows to assess the impact of using different receivers with different settings on an individual calibration. 
Previous studies already have shown, that the geodetic receivers used during the absolute calibration of antennas have an impact on the estimated PCC. However, currently this impact is only analysed at the level of the respective patterns and not in the coordinate domain. Moreover, the results are always only valid for the respective antenna-receiver combination. Therefore, more samples of different combinations are required.
In this contribution, we study calibration results of several antenna-receiver combinations using a zero baseline configuration during the calibration process in order to assess the receiver’s impact due to different signal tracking modes. The resulting PCC are analysed on the pattern level regarding (i) the repeatability of individual calibrations and (ii) differences between different antenna-receiver combinations. Finally, the impact of the different PCC are validated in the coordinate domain by a well controlled short baseline and common clock set-up. Here, again a zero baseline configuration with the identical receivers used during the calibration process is performed. Consequently, the impact of the respective antenna-receiver combination with individually estimated PCC on the positioning is analysed.