The carrier phase variance components from different receivers and different types of satellite were estimated based on the sigma-ε model. The results implied that the variation of these components was closely related to the types of the receivers and satellites. In order to establish more realistic stochastic model, this paper combined the least square method with MINQUE method to estimate the variance components from different type of satellites in real-time.Experiments were carried out to evaluate its performance.The results showed that: 1) In short baseline case, this method is able to improve the solution accuracy and stability of relative positioning;and 2) Compared with empirical models, the azimuth accuracy and range are improved by about 10%, and the accuracy and range in North, East, and Up directions are also improved by about 5% to 10%.