Abstract: The extracting method of the relative velocity,the miss distance and the miss time parameters of the target in miss-distance measurement system is investigated.The four-parameter basis functions decomposition of time-frequency signal representation is presented based on the characteristics of Doppler frequency of the radar echoes,thereby dopplerlet transform is introduced.Miss distance parameters are estimated by matching pursuit algorithm to search the basis function which best matches the echo signal.The experimental results have shown that the proposed method is effective for the estimation of miss-distance parameters and is simpler and more exact than others.