Approach for high‐resolution inverse synthetic aperture radar imaging of ship target with complex motion

Abstract

High-resolution inverse synthetic aperture radar (ISAR) imaging of ship target has attracted the attention of many scholars all around the world. For the complex motion of the ship, the Doppler frequency shifts of the scatterers are actually time-varying, and the received signals in a range bin can be characterised as multi-component amplitude-modulated and frequency-modulated (AM-FM) signals. In this study, the AM-FM signals are approximated as a weighted sum of multiple Chirplets, and a novel approach for high-resolution ISAR imaging of ship target based on the product cubic phase function (PCPF) for Chirplet decomposition is proposed. The PCPF algorithm can reduce the cross-terms between different Chirplet components, and combined with the range-instantaneous-Doppler technique, the high-resolution instantaneous ISAR images can be obtained. Results of simulated and real data demonstrate the effectiveness of the method proposed.

Inverse Synthetic Aperture Radar Imaging of Nonuniformly Rotating Target Based on the Parameters Estimation of Multicomponent Quadratic Frequency-Modulated Signals

“…where MC P F cross (n, ) is the cross-term with the form of: We can see from (15) and (16) that, when a 13 = a 23 , the auto-terms for |MC P F (n, )| can be detected correctly, and the quadratic phase coefficients a 12 and a 22 can be estimated.…”

“…The most commonly used signal model is the linear-frequencymodulated (LFM) signal, where it is assumed that the maneuverability of noncooperative target is not too severe, and the Doppler frequency shift for different scatterers can be approximated as a first order polynomial. Many ISAR imaging algorithms based on LFM signal model have been proposed, include the Hough-Wigner transform [10], the match Fourier transform [11], the Dechirp method combined with the CLEAN technique [12] and the signal decomposition algorithm [13]- [15]. For the target with high maneuverability, the LFM signal model is not accurate enough to generate a well focused instantaneous ISAR image.…”

Radar Imaging of Non-Uniformly Rotating Targets via a Novel Approach for Multi-Component AM-FM Signal Parameter Estimation

“…Then, the Chirplet atom can be further dechirped to a sinusoidal signal, and the time center $t_k$ can be estimated by the Wigner-Ville distribution (WVD) for the sinusoidal signal with the peak position. The detailed implementation of it can be found in [30]. …”

“…Step 8 : The other parameters, including ${\omega }_k$ , ${\sigma }_k$ and $C_k$ can be estimated by the Fourier transform and the similar algorithm as in [30];…”

Inverse synthetic aperture radar imaging of maneuvering target based on cubic chirps model with time-varying amplitudes

“…[1][2][3][4][5] The primary step for ISAR imaging is motion compensation, and this can be well implemented by the traditional methods. [1][2][3][4][5] The primary step for ISAR imaging is motion compensation, and this can be well implemented by the traditional methods.…”