面向复杂地形的多通道干涉SAR高精度DEM稳健反演研究

To solve the hard problem of robust DEM inversion with high precision for the complicated and abrupt terrain, this project will concentrate on how to exploit the multichannel InSAR technique. (1)The constraint model of the multichannel InSAR system parameters(especially the baselines’ lengths and their length ratios) on the DEM precision and algorithm’s robustness will be revealed based on the deep analysis of the relationship of the DEM precision and the system parameters, which will provide theory evidence for the optimal design of the system parameters and the DEM inversion algorithms. (2)The intrinsic relationship of the interferometric phase noise and the phase gradient estimation precision will be investigated, and the method of overcoming the inaccurate phase gradient estimation caused by the phase noise and the phase jump will be researched, which will lay a foundation for the application of the phase gradient information in the multichannel InSAR DEM inversion algorithms. (3)The method of robust DEM inversion with high precision for multichannel InSAR based on the fusion of phase gradient information and filter technique will be studied to solve the problem of current method’s instable performance and high complexity. .The findings of the project will provide a theory evidence for the stable and fast DEM inversion with high precision, which has great significance for the topographic survey of the complicated area successfully in the future. The DEM precision and the algorithm’s robustness is also supposed to be improved by the research. It has considerable theoretical significance, exploration worth, and application prospect for further promoting the application of InSAR in the earth observation field.

针对在地形复杂及突变区域稳健地实现高精度DEM反演这一难点问题，本项目拟利用多通道干涉SAR技术进行研究：（1）研究多通道干涉SAR系统参数（尤其是基线条数及基线间长度比例关系）对高程精度及算法稳健性的约束关系，提出合理的系统参数及基线构型设计方案；（2）研究干涉相位噪声及相位跳变与相位梯度估计精度之间的内在联系，提出可克服相位噪声、相位跳变等因素限制的相位梯度估计方法，为相位梯度信息在多通道干涉SAR高程反演算法中的应用奠定基础；（3）探索相位梯度信息和滤波技术的融合方式，提出稳健的多通道干涉SAR高精度DEM反演方法，有效解决现有方法性能不稳定和复杂度较高的问题。.通过以上研究解决复杂测绘地区的稳定快速高精度DEM反演问题，提高DEM反演精度和算法稳健性，对于进一步推动干涉SAR在对地观测领域的应用具有重要的理论意义、探索价值和应用前景。

针对在地形复杂及突变区域稳健地实现高精度DEM反演这一难点问题，本项目利用多通道InSAR技术进行了相关研究。（1）研究了平台高度、下视角、目标斜距、基线条数、基线比率、基线长度和基线侧滚角等系统参数对DEM反演精度的影响，构建了系统参数与DEM反演精度之间的约束模型，分析了基线长度比例关系对多通道InSAR高程反演算法稳健性的影响，提出了一种最优基线组合策略，为基线构型的设计及后续DEM反演方法的选择提供了参考依据；（2）针对现有多通道InSAR高程反演方法鲁棒性不强的问题，研究了基于相位梯度信息和滤波技术的多通道InSAR高程反演方法，提出了基于类相位滤波和聚类分析的闭合鲁棒多基线相位解缠方法，还提出了基于公共余数最优估计的多通道InSAR高程反演方法；（3）针对单航过InSAR系统通道不平衡导致干涉相位误差的问题，研究了下采样条件下InSAR系统高频内定标信号采样频率的选择及其相应的测量方法，为单航过多基线InSAR系统通道平衡设计提供了参考依据；（4）针对传统多通道InSAR干涉图仿真方法没有考虑叠掩和阴影影响，以及当前用于多通道InSAR高程反演的合适干涉数据集欠缺的问题，提出了一种顾及叠掩和阴影的多通道InSAR干涉图仿真方法，并给出了InSAR干涉图中叠掩区和阴影区的几何判别法。. 通过以上研究，提高了利用多通道InSAR技术进行DEM反演的精度和稳健性，对于进一步推动InSAR在对地观测领域的应用具有重要的理论意义、探索价值和应用前景。