A high-precision nominal flight profile,involving controllers′intentions is critical for 4Dtrajectory estimation in modern automatic air traffic control systems.We proposed a novel method to effectively improve the accuracy of the nominal flight profile,including the nominal altitude profile and the speed profile.First,considering the characteristics of trajectory data,we developed an improved K-means algorithm.The approach was to measure the similarity between different altitude profiles by integrating the space warp edit distance algorithm,thereby to acquire several fitted nominal flight altitude profiles.This approach breaks the constraints of traditional K-means algorithms.Second,to eliminate the influence of meteorological factors,we introduced historical gridded binary data to determine the en-route wind speed and temperature via inverse distance weighted interpolation.Finally,we facilitated the true airspeed determined by speed triangle relationships and the calibrated airspeed determined by aircraft data model to extract a more accurate nominal speed profile from each cluster,therefore we could describe the airspeed profiles above and below the airspeed transition altitude,respectively.Our experimental results showed that the proposed method could obtain a highly accurate nominal flight profile,which reflects the actual aircraft flight status. A high-precision nominal flight profile, involving controllers of transmissions is critical for 4D trajectory estimation in modern automatic air traffic control systems. We propose a novel method to effectively improve the accuracy of the nominal flight profile, including the nominal altitude profile and the speed profile .First, considering the characteristics of trajectory data, we developed an improved K-means algorithm. Approach was to measure the similarity between different altitude profiles by integrating the space warp edit distance algorithm, thereby to acquire several fitted nominal flight altitude profiless.This approach breaks the constraints of traditional K-means algorithms. Second, to eliminate the influence of meteorological factors, we introduced historical gridded binary data to determine the en-route wind speed and temperature via inverse distance weighted interpolation. Finally, we facilitated the true airspeed determined by speed triangle relationships and the calibrated airspee determined by aircraft data model to extract a more accurate nominal speed profile from each cluster, therefore we could describe the airspeed profiles above and below the airspeed transition altitude, respectively. Our experimental results showed that the proposed method could obtain a highly accurate nominal flight profile, which reflects the actual aircraft flight status.