Focusing of high range resolution profiles of moving targets using stepped frequency waveforms

A new approach is presented to remove the motion effect of a maneuvering target in a high range resolution (HRR) profile based on stepped frequency waveform (SFW). The effects of target´s motion in the SFW HRR profile consists of dispersion and translation shift of HRR profiles. The proposed approach exploits a subarray averaging concept in conjunction with the entropy cost function in order to find the translational velocity and acceleration of the target. By making use of the inherent properties of the proposed entropy-based cost function, the authors devise an efficient scheme for the two-dimensional (2-D) optimisation problem in the velocity and acceleration space, thereby improving the computational efficiency as well as the estimation accuracy significantly. Once the kinematic motion parameters are known, the unwanted dispersion of HRR profiles caused by the target´s motion can be easily removed, providing focused HRR profiles with no dispersion. The proposed algorithm is especially useful for SFWs having low pulse repetition frequencies (PRFs) rather than those with high PRFs. The effectiveness of the algorithm is illustrated and analysed with simulated targets comprised of point scatters and a real aircraft radar cross-section data with artificial motion effects.