不同分布模式电离层对星载InSAR测高精度的影响及校正

电离层总电子含量(TEC)会使合成孔径雷达干涉测量(In SAR)信号产生相位延迟,进而影响生成DEM的精度,特别是对L和P等长波段信号的影响不可忽略。因此,针对不同TEC分布模式的电离层开展研究,构建了电离层对星载In SAR测高精度的影响模型,提出了相应的校正方法,并进行了仿真实验。实验表明对于特定波长的In SAR信号,不同TEC分布模式对In SAR测高精度的影响不同:TEC均匀分布的电离层模型对In SAR测高精度的影响较小,并可通过相位解缠、基线估计等环节进行很好的补偿;而TEC不均匀分布的电离层模型对In SAR精度的影响较大,仅靠相位解缠等过程不能较好地消除,必须通过向干涉图中加入电离层影响模型予以纠正。

Influence and Correction of Different Distribution Patterns Ionosphere on Spaceborne InSAR Elevation Measurement Accuracy

The total electron content ( TEC) of the ionosphere will cause InSAR signal phase delay, thereby affect-ing the accuracy of DEM, especially the effect on L, P and other long wavelength signals can' t be ignored. There-fore, the research was carried out for different distribution patterns of TEC, the model of ionosphere effect on spa-ceborne InSAR measurement precision was constructed, then the corresponding correction methods were proposed and simulation experiment was carried out. The experimental results show that for a particular wavelength of the In-SAR signal, the effects of the different distribution patterns of TEC on InSAR measurement accuracy are different:the impact of the uniform distribution of TEC on InSAR measurement precision is less, and the effect can be well compensated through phase unwrapping and baseline estimate; for the uneven distribution of TEC, the impact is greater, and it can' t be eliminated well through phase unwrapping and baseline estimate, it must be corrected by adding ionosphere effect model to the interference pattern.