Abstract: In view of the disadvantages in the traditional orbit determination method,such as complicated orbit elements solving, low real time filtering accuracy, uncertain systematic errors and so on, this paper presents and explicates a method of real time orbit determination using self- calibration kalman filter with restrictions. The characteristics of the method are little complicacy, good real time distinction and small computational cost. Simulation results indicate that quick converging and high orbit determination accuracy are also the advantages of the method. There is much prospect of the method being put in practice.