Inverse Synthetic Aperture Radar (ISAR) Imaging of Targets with Non-Uniform Motion

The unknown relative movement of the targets with respect to radar, cause blurring image formation based on RD algorithm; because this algorithm is used for imaging of the targets with uniform motion during the coherent processing interval (CPI). In the other words, doppler frequency shift must remain constant during the image formation time; but in real scenario, targets have non-uniform and unknown motion relative to radar and doppler frequency shift is time-varying. For this reason, in this paper, we change the RD algorithm to extract image from non-uniform targets by target motion parameters estimation. Then, the impact of the removal of the residual phase in receive signal and rotational motion compensation on the invariance of doppler frequency shift of the scatterer points will be indicated. The simulation results of the proposed algorithm from raw data to final image formation show the effectiveness of this algorithm.