Although ground-based synthetic aperture radar (GB-SAR) interferometry has a very high precision with respect to deformation monitoring, it is difficult to match the fan-shaped grid coordinates with the local topography in the geographical space because of the slant range projection imaging mode of the radar. To accurately identify the deformation target and its position, high-accuracy geocoding of the GB-SAR images must be performed to transform them from the two-dimensional plane coordinate system to the three-dimensional (3D) local coordinate system. To overcome difficulties of traditional methods with respect to the selection of control points in GB-SAR images in a complex scattering environment, a high-resolution digital surface model obtained by unmanned aerial vehicle (UAV) aerial photogrammetry was used to establish a high-accuracy GB-SAR coordinate transformation model. An accurate GB-SAR image geocoding method based on solution space search was proposed. Based on this method, three modules are used for geocoding: framework for the unification of coordinate elements, transformation model, and solution space search of the minimum Euclidean distance. By applying this method to the Laoguanjingtai landslide monitoring experiment on Hailuogou Glacier, a subpixel geocoding accuracy was realized. The effectiveness and accuracy of the proposed method were verified by contrastive analysis and error assessment. The method proposed in this study can be applied for accurate 3D interpretation and analysis of the spatiotemporal characteristic in GB-SAR deformation monitoring and should be popularized.

中文翻译：

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基于解空间搜索的GB-SAR图像精确地理编码方法及其在滑坡监测中的应用

尽管地面合成孔径雷达（GB-SAR）干涉仪在变形监测方面具有非常高的精度，但是由于倾斜范围投影成像，很难将扇形网格坐标与地理空间中的局部地形进行匹配雷达模式。为了准确识别变形目标及其位置，必须对GB-SAR图像进行高精度的地理编码，以将其从二维平面坐标系转换为三维（3D）局部坐标系。为了克服传统方法在复杂散射环境中选择GB-SAR图像中控制点的困难，利用无人机（UAV）航空摄影测量获得的高分辨率数字表面模型，建立了高精度的GB-SAR坐标转换模型。提出了一种基于解空间搜索的精确GB-SAR图像地理编码方法。基于此方法，三个模块用于地理编码：坐标元素统一框架，转换模型以及最小欧几里得距离的解空间搜索。通过将该方法应用于海螺沟冰川老关井台滑坡监测试验，实现了亚像素地理编码精度。通过对比分析和误差评估验证了该方法的有效性和准确性。