Motion parameter estimation of multiple ground fast-moving targets with a three-channel synthetic aperture radar

This study presents a novel motion parameters estimation technique for moving targets, including those with velocities beyond the Nyquist limit in multi-channel synthetic aperture radar data. The technique proposed in this study exploits the linear dependence between the fold factor of the cross-track velocity and the slope of the moving target trajectory in the range compressed and azimuth time domain after performing Keystone transformation in the range frequency and azimuth time domain. The velocity ambiguity thus can be overcome. The along-track velocity can be retrieved from the chirp rate estimated by applying a new time-frequency analysis method called Keystone-Wigner transform. The algorithm of motion parameter estimation efficiently converts the two-dimensional (2-D) search into the two separate 1-D cases. The proposed method can robustly estimate the motion parameters of the fast-moving targets, which are illustrated both with simulated and real data.