Summary:

Surveying devices like tachymeters and levels might be monitored and if it is necessary - calibrated. Similar procedures should apply to GNSS (Global Navi-gational Satellite System) measuring sets.
The semi-calibrating research on two GNSS antennas (Trimble 5800) shows that antennas are different and the calibration files have different influence on both. it means that probably individual calibrations files are needed.
Antenna calibration and correct orientation of antenna during the GNSS survey may lead to better positions' accuracies.