GNSS antenna phase center variation calibration for attitude determination on short baselines

CubETH is a satellite project aimed at technology demonstration. One of the mission goals is the determination of the attitude of the 10 x 10 x 10 cm(3) spacecraft with GNSS. First tests revealed that Phase Center Variations (PCV) dominate the error budget. In consequence, a simple field method for PCV calibration of antenna systems was developed. The estimated PCV confirms the hypothesis of mutual influence of the antennas. A simulation study using the estimated pattern and a validation with real data proved that the PCV calibrations significantly enhance the accuracy of the attitude determination. The root mean square error of the estimated attitude of a platform with three antennas located within 15 cm of each other could be reduced from 6 degrees to 4.5 degrees. The newly developed calibration method is easy to carry out and will help to enhance the accuracy of GNSS attitude determination systems.