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摘要: 利用干涉合成孔径雷达(InSAR)技术获取数字高程模型(DEM)时,在地形起伏剧烈区域,干涉条纹十分密集,增加了相位解缠的难度,影响相位展开和高程反演的精度。为了解决该问题,该文提出了一种基于DEM辅助后向投影模型的InSAR高程反演方法。该方法可以在统一的后向投影成像空间中实现成像和InSAR高程反演,并且引入外源DEM作为辅助信息,去除大部分地形相位,有效地降低了干涉条纹的密度,减少了干涉相位的缠绕。此外,该方法在多数情况下可以避免图像配准和相位解缠过程,简化了传统InSAR的处理流程,并且可以实现高精度的高程反演。通过仿真实验和X波段机载双天线InSAR数据的处理验证了该方法的有效性。Abstract: When Interferometric Synthetic Aperture Radar (InSAR) is used to obtain the Digital Elevation Model (DEM), highly sloped terrains will make interferometric fringes dense and increase the difficulty of phase unwrapping, which will affect the accuracy of phase unwrapping and elevation inversion. To solve this problem, an InSAR elevation inversion method based on BackProjection (BP) model with an external DEM is proposed. This model achieves imaging and InSAR DEM inversion in a uniform BP geographic space and introduces an external DEM as auxiliary information. These processes, in turn, can remove most phases of the terrain and reduce the density of interferometric fringes and phase wrapping. Additionally, the proposed method can avoid the procedures of image registration and phase unwrapping in most cases, which simplifies traditional InSAR processing and achieves high processing accuracy. A simulation experiment and X-band InSAR data processing were performed to verify the effectiveness of the proposed method.
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Key words:
- Elevation inversion /
- InSAR /
- External DEM /
- BackProjection (BP) algorithm /
- SAR
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表 1 仿真参数
Table 1. Simulation parameters
成像仿真参数 数值 载频(GHz) 9.6 距离向带宽(MHz) 100 距离向采样率(MHz) 120 脉冲宽度(μs) 3.7 脉冲重复频率(Hz) 300 平台平均速度(m/s) 113.5 平台平均高度(m) 3286.5 中心下视角(rad) 0.8727 基线长度(m) 2.189 基线倾角(rad) 0 表 2 X波段机载InSAR系统参数
Table 2. X-band airborne InSAR system parameters
机载InSAR参数 数值 载频(GHz) 9.6 距离向带宽(MHz) 300 距离向采样率(MHz) 500 脉冲宽度(μs) 15 脉冲重复频率(Hz) 1000 平台平均速度(m/s) 108 平台平均高度(m) 4874 中心下视角(rad) 0.7854 基线长度(m) 1.05 基线倾角(rad) –0.2358 表 3 地面检查点处高程反演误差
Table 3. The elevation inversion errors of ground detection points
地面检查点 本文方法(m) 传统InSAR方法(m) 1 –0.5765 –0.8017 2 –0.1310 –0.0824 3 0.7075 0.8840 标准差 0.6519 0.8459 -
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