Abstract: By applying the scaled UT(Unscented Transform) to a general sampling strategy,the problem of non-local effects of sampling can be resolved,and the estimating precision of UKF(Unscented Kalman Filter) can be improved as well.The scaling factor is one of the most important parameters,so a self-adaptive selecting method for the scaling factor was proposed.The self-adaptive scaled UT was applied to the scaled minimal skew simplex sampling,and the relevant UKF was applied to the real-time orbit determination of Low-Earth satellites.Simulation results indicate that the method is of high stability,and the relevant precision of the orbit determination approaches to the precision of the UKF with an optimal fixed scaling factor.