Analysis of time-variant IPP and ISAR imaging for non-cooperative targets with highly maneuvering motion

Due to complex motion of translational motion (TM) and three-dimensional rotational motion (RM) co-exits for noncooperative targets, existing inverse synthetic aperture radar (ISAR) imaging approaches cannot produce satisfactory performance, especially under low signal-to-noise ratio (SNR). Therefore, an efficient inverse synthetic aperture radar (ISAR) imaging approach for non-cooperative targets is proposed in this work. First, the imaging geometry and signal model are reasonably established based on the highly maneuvering characteristic for non-cooperative targets. Second, based on the signal model, the resolution in range dimension and azimuth dimension, the time-variant Doppler frequency, the selection of pulse repetition frequency (PRF), and the non-stationary IPP are theoretically analyzed. Furthermore, aiming to the time-variant characteristic of echo signal, the smooth pseudo Wigner-Ville distribution (SPWVD) method is utilized to ISAR imaging for non-cooperative targets. Finally, both simulated and electromagnetic data validate the effectiveness of the signal model.