Abstract: The method of RVD relative navigation based on relative differential pseudo range of GPS was studied.Firstly,the model error was analyzed when the measure model was linearized at the zero position of relative position,and the bias of relative navigation parameters caused by model error was also induced.Then two better methods that one of correction of model error and the other of nonlinear filter by Strong Tracking Filter were proposed.Finally,computer simulation shows the feasibility of these new methods.