ResearchMain Research FocusAntenna CalibrationGNSS Antenna's Near Field
Characterisation of the standard substructure FG-AN 100B

Characterisation of the Standard Substructure FG-AN 100B


  • © IfE / T. Kersten

    Standardunterbau FG ANA100B mit Leica GST120 Stativkopf

  • © IfE / T. Kersten

    Trimble Antenne TRM33429.20 mit Grundplatte

  • © IfE / T. Kersten

    Höhenadaption mit Nahfeldumgebung

  • © IfE / T. Kersten

    Weitere Höhenadaption mit zusätzlicher Metallplatte

In order to prevent station-dependent variations in the near field of the antennas, a standardized substructure was chosen for the DHHN campaign 2006 - 2011.  These near-field influences can be introduced into the environment of the antenna in a controlled manner, if the near-field of the antenna is precisely defined in geometry and external orientation during calibration. For this purpose, investigations were performed with a trimble antenna TRM33429.20+GP (S/N 0220132683) and the standardized antenna height measuring adapter FG-ANA 100B (tripod Freiberger Dreifuss - SFD) in different arrangements and with two different receivers (Javad Legacy and Trimble 4700).

Figures 1-4 show the different setups. The antenna height measuring adapter was kindly provided by the LGLN Hannover.


Elevation-dependent phase variations during the calibration of different antenna/substructure/receiver combinations. Shown are the dPCV with regard to calibration with a standardized substructure.

In order to perform a strict comparison of the phase variations, the individual phase centres were transformed to a uniform phase centre (calibration with SFD). The results show a clearly different behaviour of the PCV of the different setups (up to 4 mm) on the signal L1 for the range of low elevations (0-20°). The use of different receiver hardware could also be detected. For a JPSLegacy and a Trimble 4700 this was shown during this experiment. There were no significant differences on signal L1. On signal L2, however, differences of 3-4 mm with identical antenna setup were observed, which are due to the individual signal processing of the receivers that were used. Finally, the linear combination used to evaluate the GPS measurements can increase the effect of the near field.