HR: 0800h
AN: G21A-0093    [Abstracts]
TI: Preparing for Galileo - New Results from Anechoic Chamber Absolute Antenna Calibrations
AU: * Becker, M
EM: becker@ipg.tu-darmstadt.de
AF: Institute of Physical Geodesy, Darmstadt University of Technology, Petersenstrasse 13, Darmstadt, 64287, Germany
AU: Zeimetz, P
AF: Institute for Geodesy and Geoinformation, University of Bonn, Nussallee 17, Bonn, 53115, Germany
AU: Schoenemann, E
AF: Institute of Physical Geodesy, Darmstadt University of Technology, Petersenstrasse 13, Darmstadt, 64287, Germany
AU: Schlueter, W
AF: Federal Agency of Cartography and Geodesy, Fundamentalstation Wettzell Sackenrieder Strasse 25, Koetzting, 93444, Germany
AU: Dow, J
AF: Navigation Office, European Space Operations Center, Robert-Bosch Strasse 5, Darmstadt, 64293, Germany
AB: The antenna phase center variations are crucial corrections for high precision GNSS applications. They are applied according to IGS conventions as absolute antenna phase center corrections which are dependent on the carrier frequency. With GLONASS As being upgraded and first Galileo signals available, this frequency dependence is getting more important and has to be clarified. Up to now extrapolation from the GPS frequencies or mean values for all GLONASS frequencies are used. Anechoic chamber antenna measurements allow for the direct phase calibration of all frequencies involved and can therefore be used to determine offset and variations for all signals. TU Darmstadt and University of Bonn developed a calibration system which allows for the efficient and quick calibration of GNSS antennas in a dedicated anechoic chamber. A series of measurements was used to calibrate GPS, GLONASS and Galileo antennas. The frequency response of all antennas and the phase pattern and offset values were determined over the frequency range of the GNSS signals in use by the different systems. In this contribution we will explain the calibration procedure and setup and give an estimation of its precision. The results of the phase pattern determinations will be given. They show a good correspondence to the recommended IGS values in use for GPS in general. The variations in phase center with frequency for the antennas tested are seen to have no clear relation to the frequency, but are significantly different for different frequencies. They are small however within e.g. the GLONASS bandwidth and probably not significant. The repeatability among different antennas of the same type has to be tested and also the overall variations have to be confirmed by more samples and further tests are planned.
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2007 Fall Meeting