Abstract: This article utilizes the Total Electron Content (TEC) data measured by the GPS stations of the Chinese Mainland Crustal Movement Observation Network (referred to as the “Crustal Network” hereafter) to establish an empirical ionospheric model for the Beijing-Tianjin-Hebei region. By incorporating solar flux and geomagnetic activity data, the performance of the model is enhanced. The study develops a functional model for the diurnal, seasonal variation, and geomagnetic effect components of the ionospheric TEC, using a nonlinear least squares method to fit the coefficients. A multi-parameter empirical fusion model is proposed-the Ionospheric TEC Beijing-Tianjin-Hebei Region Model (MEFM-ITBTHR) - to predict the ionospheric TEC in the Beijing-Tianjin-Hebei region. Results indicate that the MEFM-ITBTHR model fits the modeling dataset well. The performance of the MEFM-ITBTHR model is further analyzed through geographical variation, seasonal variation, and geomagnetic disturbance analysis. Results demonstrate that in the Beijing-Tianjin-Hebei region, the MEFM-ITBTHR model exhibits better forecasting accuracy, linear correlation, and model precision for measured TEC across different latitudes, seasons, and geomagnetic disturbances compared to the IRI2020 and NeQuick2 models. The regional TEC empirical model constructed in this study provides a new method for ionospheric delay correction for GNSS single-frequency users and holds significant reference value for establishing other new and improving existing empirical ionospheric models.

Key words: Empirical model, IRI2020, NeQuick2, TEC