Abstract: Aiming at the lack of effective quality control for the troposphere zenith total delay (ZTD) modeling based on GNSS observation data, a ZTD modeling quality control method that takes into account data volume, grid resolution, and model stability is proposed. Using the high spatial resolution GNSS ZTD data of 183 stations in Germany and surrounding regions ［47°N-55°N, 5°E-15°E］ in the last ten years, calculated by the Nevada Geodetic Laboratory, the method has been verified. The experimental results show that the new model established under this quality control method has stable accuracy, and the average root mean square error (RMS) is 3.4 cm, with 42.4%, 35.8% and 33.3% being improved as compared with UNB3m, EGNOS, and GPT2w+Saas respectively. The proposed quality control method helps to improve the performance of ZTD modeling and could be provided as a reference approach for ZTD modeling research.

Key words: Zenith Total Delay (ZTD), Quality control, GNSS, Nevada Geodetic Laboratory (NGL)