Abstract: The stochastic model of GPS/Doppler play an important role in the navigation solution. Two-step method for estimating the stochastic model of GPS/Doppler integrated observation is proposed. Firstly, the robustly posterior estimation is introduced according to equivalent weight principle and carrier-to-noise ratio, Then, the variance of unit weight is estimated in a moving -window in real time by combining the forgetting factor and observation redundancy. Finally, a real vehicular GPS data is carried out to test the proposed method.