Abstract: A new approach for estimating the vector miss distance parameters of the target is presented, which based on the extraction of the target motion trajectory in space. In this method, the distance differences, which are got from the phase differences of echo signals between the different receiving antennas, and the localization method based on distance differences is utilized to get the spatial localization point sequences of the target. Further the fixed-interval Kalman smoothing filter is adopted to obtain a more accurate target motion trajectory by constructing the motion model of the target. Then by utilizing the total smoothed localization point, a set of linear equations is formed and the vector miss distance parameters are estimated. Simulation results prove that the proposed method is effective in the vector miss distance parameter estimation.