Abstract:We propose a simplified model for differential code bias estimation, which simplifies the VTEC of each puncture point in the direction of the station into a parametric sub-period for direct estimation. To verify the validity of the method, a comparative analysis is performed using the spherical harmonic function modeling and the GIM estimation-based method. GPS+GLONASS data from nearly 200 IGS stations in January 2016 were selected for the experiments and validated with the products provided by CODE. The results show that for GPS(GLONASS) satellite DCB, the method is relatively close to the results estimated by the other two methods, and the mean deviation and standard deviation compared with the products of CODE are -0.3-0.5 ns (GPS)、-1.3-0.7 ns(GLONASS) and 0.05-0.20 ns (GPS)、0.14-1.10 ns(GLONASS), respectively. For receiver DCB, the mean deviation of the three methods compared with the products of CODE are -0.6-0.7 ns (GPS) and -1.5-1.5 ns (GLONASS), respectively. The experimental results verified the validity of the simplified model of DCB.