基于车载多通道探冰雷达的三维冰下地形提取方法

3-D Tomography Method Based on Ground-based Multi-channel Ice-penetrating Radar

冰盖模型的建立对于未来全球气候预测至关重要,获得准确冰下地形特征是开发更真实精确的冰盖模型的重要条件,而具有高精度探测及定位优势的车载多通道冰雷达适用于获得开发冰盖模型所需的基础信息。传统基于频率波数域(f-k)偏移的冰雷达数据处理算法仅能对行进轨迹测线下的二维冰下地形进行测量,需要地理插值才能得到三维冰下地形,插值精度影响到最终的三维地形图精度,特别是在冰流速较大区域,该地理插值方案会引起较大的地形误差。本文针对上述问题展开深入研究,结合格陵兰岛车载多通道冰雷达探测数据的处理,提出一种基于多通道冰雷达数据的三维冰下地形提取方法,利用层析处理技术结合空间谱估计方法得到精确的数字高程模型(DEM)数据,实现对冰盖的条带模式探测,具有空间分辨率高、冰下地形误差小等优点。仿真及实测数据处理结果验证了本文提出的三维冰下地形提取方法的有效性。

The establishment of ice sheet models is crucial for future global climate prediction,and obtaining accurate topo‐graphic condition is important for developing more realistic and accurate ice sheet model.The ground-based multi-channel ice penetrating radar with the advantage of high-precision detection and positioning is suitable for obtaining the basic information required for developing ice sheet models.The traditional SAR processing algorithm based on frequency-wavenumber(f-k)migration can only measure the two-dimensional along-track tomography;in order to obtain three-dimensional tomography,geo‐graphic interpolation is required.The accuracy of the geographic interpolation affects the accuracy of the final three-dimensional topographic map;this is especially in regions with high ice flow velocities.The methods mentioned above are thoroughly examined in this essay.A three-dimensional tomography method is proposed in conjunction with the processing of the ground-based multi channel ice-penetrating radar data in Greenland.The tomographic method allows for the direct measurement of digital elevation map(DEM),as well as other benefits such as the ability to detect ice sheet with high spatial resolution and minimal subglacial terrain error.Results from simulation and collected data processing demonstrate the efficacy of this three-dimensional tomographic method.