基于二阶WVD的ISAR平动补偿方法

A Translation Compensation Method for ISAR Based on Second-order WVD

  • 摘要: 逆合成孔径雷达(Inverse synthetic aperture radar, ISAR)目标成像在军事和民用领域有着很广泛地应用,近年来,ISAR目标成像技术发展已经较为成熟,然而由于观测场景复杂和目标的非合作特性,导致获取的目标图像分辨率低和出现散焦、拖尾等问题。针对上述问题,本文提出了一种基于二阶维格纳维拉分布(Wigner-viller Distribution,WVD)的ISAR平动补偿方法,该方法首先将ISAR回波信号建模为二阶多项式,然后运用Keystone变换校正由运动引起的距离走动,再利用二阶WVD变换聚焦目标所有散射体的能量,进而估计出二阶运动参数,最后通过解调操作和Keystone变换获得聚焦良好的目标图像。本文提出的方法在低信噪比(Signal-to-noise ratio,SNR)环境下具有较稳定的性能,并且避免了多维搜索,减少了运算复杂度,有利于实现ISAR运动目标的实时成像。

     

    Abstract: ‍ ‍Inverse synthetic aperture radar (ISAR) target imaging is widely used in military and civilian fields. In recent years, the development of ISAR target imaging technology has become more mature. However, due to the complex observation scene and the non-cooperative characteristics of the target, the acquired target image has low resolution and problems such as defocusing and smearing. In response to the above problems, this paper proposes an ISAR translation compensation method based on the second-order Wigner-viller Distribution (WVD). Firstly, the ISAR echo signal is modeled as a second-order polynomial, and then the keystone transform is used to correct the range walk caused by motion. Secondly, the second-order WVD transform is used to focus the energy of all scatterers of the target, and then estimate the second-order motion parameters. Finally, the target image with good focus is obtained by demodulation and keystone transform. The proposed method has stable performance in low signal-to-noise ratio (SNR) environment, and avoids multi-dimensional search, and reduces the computational complexity, which is conducive to real-time imaging of ISAR moving targets.

     

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