Monitoring of antenna changes at IGS stations in Iceland

GNSS antenna changes are in particular critical for the long-term stability of the coordinate time series and the reference systems realized with these stations. Depending on the antenna types and the available antenna calibrations, discontinuities of up to several centimeters can be introduced. Therefore, a monitoring of the antenna changes is important to verify the continuity of the time series. In order to add Galileo tracking capability the GNSS equipment at the Icelandic IGS stations Reykjavik and Hoefn had to be replaced. Temporary GNSS sites were set up in the vicinity of both sites. These short baselines are analyzed with different observables. In addition, the temporary sites were included in the routine processing of the Center for Orbit Determination in Europe analysis center of the IGS. The equipment changes introduced discontinuities of up to 1.5 cm in the coordinates derived from the global solution. Depending on the analysis strategy and observables used, the results of the short baselines differ by up to 2.5 cm.