Cross-range scaling method of inverse synthetic aperture radar image based on discrete polynomial-phase transform

• Published in: IET radar, sonar & navigation sonar & navigation, 2015-03, Vol.9 (3), p.333-341
• Main Authors: Liu, Lei, Zhou, Feng, Tao, Ming-liang, Zhao, Bo, Zhang, Zi-jing
• Format: Article
• Language: English
• Subjects: Angular velocity; cross‐range scaling method; discrete polynomial‐phase transform; discrete transforms; Echoes; frequency domain windowing; Inverse synthetic aperture radar; inverse synthetic aperture radar image; least squares approximations; least‐square‐error method; Radar; Radar imagery; radar imaging; radar line‐of‐sight; radar wavelength; range geometry; Rotating; rotating angular velocity; Scatter; second‐order phase coefficients; synthetic aperture radar; the translational motion; Transforms
• ISSN: 1751-8784; 1751-8792
• DOI: 10.1049/iet-rsn.2013.0392

The cross-range scaling of inverse synthetic aperture radar image depends on both the radar wavelength and the rotating angle of the target relative to the radar line-of-sight. After compensating the translational motion, the second-order phase coefficients of the range echoes are a linear polynomial of the rotating angular velocity and range geometry. In this study, a novel method for estimating the rotating angular velocity of the targets with dominant scatters is proposed. The range cells where the amplitudes have smaller normalised variances are selected, and then frequency domain windowing is applied to extract echoes of dominant scatters. Based on the discrete polynomial-phase transform, the second-order phase coefficients of the strong scatter echoes are estimated, and thus the rotating angular velocity can be obtained through the least-square-error method. Simulated and real-data results have shown the effectiveness and robustness of this method.