Analysis of the Accuracy of Quasi-Geoid Models Used in GNSS Altitude Measurements

The paper contains the results of verification of the usefulness of quasi-geoid models distributed with GNSS receivers on the example of Trimble R6 and South S82-T systems. As reference points geodetic control networks of 2nd and 3rd class were used. Comparing the normal heights H determined on the basis of precise levelling and GNSS measurement using the quasigeoid models, it was found that not all provided models meet the accuracy requirements set by the current provisions of law. The elevation survey using the GNSS method must therefore be preceded by the receiver's vertical calibration or usage of the verified quasi-geoid model. This approach can be implemented directly during field measurement using the functions of GNSS receiver or in the office with computer software.