Impact of antenna phase center models: From observation to parameter domain

Abstract

For precise GNSS applications like positioning, navigation and timing (PNT) as well as for troposphere studies, stable and accurate calibrations of the carrier phase center variations (PCV) for individual antennas have to be provided by calibration institutions. Beside an anechoic chamber calibration, the Institut für Erdmessung (IfE) uses a field approach with a precisely calibrated robot. Ring analyses between different calibration institutions determined with geodetic graded antennas show comparability at the level of 1mm which is a threshold accepted by the International GNSS Service (IGS). Several contributions and papers discuss the impact of the variability of calibration models on the coordinate or parameter domain, respectively. This can only be a first approximation since complex interactions depending on the processing philosophy, propagates PCVs differently to the parameters, so that unexpected discrepancies on the parameter domain can occur and have to be analysed consequently. This contribution presents a concept to study the impact of PCVs on the observation and parameter domain. In this concept the PCVs will be formulated not as classical tabulated PCV models but with their corresponding spherical harmonic (SH) coefficients. Finding a transfer function to analytically study the impact of the PCVs on the individual parameter like i.e. coordinates, time and troposphere as well as ambiguities is one of the three main goals in this concept. Exemplarily we will show first results and will study error functions between type and individual calibration models based on the proposed concept.