The influence of GPS antennas calibration parameters in ellipsoidal heights in relative static positioning

Abstract:

High accuracy in GPS (Global Positioning System) positioning is obtained by partial or total errors eliminating present in the observations, particularly the systematic ones. One of them is called GPS antenna phase center error. It is directly dependent on the antenna used because each antenna has its own design characteristics and GPS signal reception. Therefore, it is extremely important to know the individual antenna phase center variation (Phase Center Offset - Phase Center Variation). There are parameters provided by the NGS (National Geodetic Survey), however, they are mean values and not individual values of the antennas used in GPS positioning. In this work individual parameters were provided by BCAL/UFPR (Base de Calibração de Antenas GNSS na UFPR). GPS surveys were carried out in nine (9) points. These were divided into three (3) baselines groups (9 km, 45 km and 105km). For each baseline length the GPS surveys were simultaneous and the Method Static Relative Positioning was applied, with an interval of data recording of 15 seconds and 15º elevation mask. Differences up to one centimeter were found when comparing the ellipsoidal heights and baselines length obtained using the BCAL/UFPR parameters and the NGS ones. In fact, the values obtained with the BCAL/UFPR parameters are derived using own parameters to the antennas used, whereas those provided by the NGS are mean values. It is noteworthy that the BCAL/UFPR is the first antenna calibration site GPS/GLONASS in Brazil and Latin America

Keywords:
Global Positioning System; High Accuracy; Antenna Calibration; Positioning; BCAL/UFPR