Abstract: In highly dynamic GNSS simulation systems, since there is a contradiction between precision and calculated volume, a method of real-time high precision pseudorange calculation based on the third-order Hermite interpolation is proposed. In this method, a satellite orbit is computed by an interpolation algorithm and the sequences of the error computation is changed to optimize the pseudorange calculations. Then, by knowing the pseudoranges and derivatives for two nodes, the parameters of the pseudorange change model was computed by a third-order Hermite interpolation algorithm. The pseudorange derivative was obtained by the second order derivative Lagrange interpolation formula. The highly dynamic simulation results show that when the time interval is 1 s, the maximum pseudo-range error is 0.638 mm, and the standard deviation is 0.172 mm.