Wang Tung-Cheng, Kiang Jean-Fu
Graduate Institute of Communication Engineering, National Taiwan University, Taipei 10617, Taiwan.
Sensors (Basel). 2025 Apr 28;25(9):2781. doi: 10.3390/s25092781.
Rogue waves are reported to wreck ships and claim lives. The prompt detection of their presence is difficult due to their small footprint and unpredictable emergence. The retrieval of sea surface height via remote sensing techniques provides a viable solution for detecting rogue waves. However, conventional synthetic aperture radar (SAR) techniques are ineffective at retrieving the surface height profile of rogue waves in real time due to nonlinearity between surface height and normalized radar cross-section (NRCS), which is not obvious in the absence of rogue waves. In this work, a cross-track interferometric SAR (XTI-SAR) imaging approach is proposed to detect elusive rogue waves over a wide area, with sea-surface profiles embedding rogue waves simulated using a probability-based model. The performance of the proposed imaging approach is evaluated in terms of errors in the position and height of rogue-wave peaks, the footprint area of rogue waves, and a root-mean-square error (RMSE) of the sea-surface height profile. Different rogue-wave events under different wind speeds are simulated, and the reconstructed height profiles are analyzed to determine the proper ranges of look angle, baseline, and mean-filter size, among other operation variables, in detecting rogue waves. The proposed approach is validated by simulations in detecting a rogue wave at a spatial resolution of 3 m × 3 m and height accuracy of decimeters.
据报道，异常海浪会造成船只失事并导致人员伤亡。由于其覆盖面积小且出现不可预测，因此很难及时检测到它们的存在。通过遥感技术反演海面高度为检测异常海浪提供了一种可行的解决方案。然而，由于海面高度与归一化雷达截面（NRCS）之间的非线性关系，传统合成孔径雷达（SAR）技术在实时反演异常海浪的表面高度剖面方面效率低下，这种非线性关系在没有异常海浪的情况下并不明显。在这项工作中，提出了一种沿航迹干涉合成孔径雷达（XTI-SAR）成像方法，用于在大面积区域检测难以捉摸的异常海浪，并使用基于概率的模型模拟嵌入异常海浪的海面剖面。从异常海浪波峰的位置和高度误差、异常海浪的覆盖面积以及海面高度剖面的均方根误差（RMSE）等方面评估了所提出成像方法的性能。模拟了不同风速下的不同异常海浪事件，并对重建的高度剖面进行分析，以确定在检测异常海浪时视角、基线和均值滤波器大小等其他操作变量的合适范围。通过模拟验证了所提出的方法在检测空间分辨率为3米×3米、高度精度为分米级的异常海浪方面的有效性。
