Simulation of Synthetic Aperture Radar Images for Ocean Ship Wakes
Simulation of Synthetic Aperture Radar Images for Ocean Ship Wakes
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DOI：
10.3390/rs15235521
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发表时间：
2023-11
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影响因子：
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通讯作者：
Shuya Wu;Yunhua Wang;Qian Li;Yanmin Zhang;Yining Bai;Honglei Zheng
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作者：
Shuya Wu;Yunhua Wang;Qian Li;Yanmin Zhang;Yining Bai;Honglei Zheng
为辅助复杂海况下舰船目标的检测，提出了一种数值模拟方法，在不同雷达、舰船和海面参数下，获得时变海洋舰船尾迹的合成孔径雷达（SAR）图像。该方法解决了最近的模拟，未能同时纳入不同类型的随时间变化的船舶尾流，模拟的回波数据的基础上，并讨论速度聚束（VB）的图像结果的影响的局限性。为了解决这些问题，首先，分别采用线性滤波方法、经典流体动力学模型和衰减函数法对海面时变波高和速度场、Kelvin尾流和湍流尾流进行了数值模拟。其次，利用地球物理模型函数（GMF）计算舰船尾流的后向散射场，确定随高度场和速度场变化的斜距，得到舰船尾流的原始数据。第三，通过对回波数据进行距离-多普勒算法（RDA）的脉冲压缩和距离徙动校正（RCMC），分别生成了有VB效应和无VB效应的SAR图像。我们的模拟还考虑了斑点噪声的影响。SAR成像结果表明，无论是否考虑VB效应，雷达电磁波段、极化模式、风速和相对风向对SAR图像强度都有明显影响，舰船尾迹的纹理和形态随风速、船速和相对雷达视向的变化而显著变化。当考虑VB效应时，由更强烈的波动引起的图像中的方位偏移和模糊也随着波速而增加。
To assist in the detection of ship targets in complex sea conditions, a numerical simulation method is proposed to obtain synthetic aperture radar (SAR) images of time-varying ocean ship wakes under various radar, ship, and sea surface parameters. This method addresses the limitations of recent simulations, which failed to simultaneously incorporate different types of time-varying ship wakes, simulate based on the echo data, and discuss the velocity bunching (VB) effect on the image results. To address these issues, firstly, the time-varying wave height and velocity fields of the sea surface, Kelvin wakes, and turbulence wakes are simulated using the linear filtering method, classic fluid dynamics models, and attenuation function method, respectively. Secondly, raw data of the ocean ship wakes are obtained by calculating the backscattering fields using geophysical model functions (GMFs), as well as by determining the changing slant range varying with the elevation and velocity fields. Thirdly, by applying the Range-Doppler algorithm (RDA) for pulse compression and range cell migration correction (RCMC) on the echo data, SAR images with and without the VB effect are generated. Our simulation also accounts for the influence of speckle noise. The SAR imaging results indicate that whether the VB effect is considered or not, the radar electromagnetic wavebands, polarization modes, wind speeds, and the relative wind directions have distinct impacts on the SAR image intensity, and the texture and morphology of ship wakes vary significantly with the wind speeds, ship speeds, and the relative radar looking directions. When considering the VB effect, the azimuthal offset and blur in the images caused by the more intense wave motion also increase with the wave speeds.