Impact of different phase center correction values on GNSS-based positioning and frequency transfer

Abstract

For precise GNSS-based positioning and stable frequency transfer, it is mandatory to take antenna Phase Center Corrections (PCC) into account. They are determined either in an anechoic chamber using simulated signals or in the field using a robot and real GNSS-signals. The PCC are provided as a grid with a typical step size of 5° elevation and azimuth angles in the Antenna Exchange (ANTEX) format as individual calibrations or alternatively as type-mean values. For the same antenna type, PCC differences (dPCC) are present between results from different calibration methods, as well as between individual and type-mean values. In previous work, we proposed a comparison strategy for dPCC. From that, we developed a standardized simulation approach, which allows assessing the impact of multi-GNSS dPCC on station coordinates, troposphere and clock w.r.t. changing processing parameters. Our studies show that the up-component and clock parameter are affected by up to 1 cm.

In our contribution, we use the simulation approach to assess the impact of dPCC on EUREF Permanent Network (EPN) station coordinates, clock and troposphere parameters. We will study dPCC between individual and type-mean calibrations. In addition, the impact of different PCC sets on GNSS-based frequency transfer stability will be investigated by means of Allan deviation. To this end, differential receiver clock time series from single differences and PPP approaches are used. We will characterize the noise process apparently induced by dPCC, its magnitude as well as variations with changing satellite geometry and varying PCC grid resolutions.