Calibration of GNSS antennas

Today it is possible to make positioning with high accuracy by using GNSS. Precise positioning is required especially for the national and international reference networks, monitoring crustal movements and deformation of the engineering structures. Getting high accuracy observations through GNSS is only possible by choosing the correct measuring method, eleminating the error sources and using the suited models for evaluating the observations. One of the error sources that have to be considered for precise positioning is the antenna phase center variations. The antenna phase center variation is determined by using suitable calibration methods and then delivered to the user. This issue includes the research and the results for defining the antenna phase center and determining level of variation.