Abstract: In order to analyze the micro-movement component of the ballistic targets at the middle trajectory, the accurate estimation and compensation of the high-speed translational component from the radar echo are needed. The ultra-wideband signal model under the joint action of the target high-speed translational movement and micro-movement is proposed, and a state space approach based method for accurately estimating translational radial velocity is presented. This method can effectively inhibit the influence of the micro- movement component on the translational radial velocity estimation, and provide better estimation accuracy than traditional methods. The ultra-wideband signal model containing both high-speed translational components and micro-movement components can also be used directly for subsequent micro parameter extraction processing. The simulation results show the effectiveness of the signal model and the translational radial velocity estimation method presented in the paper.