利用参数独立分解的星载SAR干涉测量检校方法

Interferometric calibration method for spaceborne SAR based on independent parameter decomposition

在星载干涉合成孔径雷达中,干涉参数的准确性对高程精度起着至关重要的作用。传统干涉测量检校方法往往将影响量级不同的干涉参数组合在一起解算,无法精确获得每项干涉参数的修正量。针对此问题,本文提出一种利用参数独立分解的干涉测量检校方法。首先,根据三维重建模型,确定与干涉SAR测高有关的参数;随后,在确保几何参数精度的前提下,对干涉参数的敏感度进行定量分析;最后,采用独立检校算法解算每一项干涉参数误差,完成干涉测量检校模型的建立。本文选择陕西渭南区域4对TerraSAR-X/TanDEM-X数据进行了试验分析。结果表明,对于该试验数据,采用本文提出的参数独立分解方法,干涉测量检校后干涉结果的高程精度优于2.54 m,平原地区获取DEM的绝对高程精度优于1.21 m,山地地区获取DEM的绝对高程精度优于3.11 m,验证了本文方法的有效性和正确性,为我国平原及山区1∶25 000比例尺的干涉SAR地形图测绘提供了技术基础。

The accuracy of interferometric parameters of InSAR plays a significant role in precise digital elevation model (DEM). However, interferometric parameters are traditionally calculated jointly, making them difficult to decompose precisely. It is proposed that an interferometric calibration method based on independent parameter decomposition(IPD) by the authors.Firstly, the parameters related to the interferometric SAR measurement are determined based on the three-dimensional reconstruction model. Secondly, the sensitivity of interferometric parameters is quantitatively analyzed after the geometric parameters are completely decomposed. Finally, each interferometric parameter is calculated based on IPD and interferometric calibration model is established. Weinan of Shanxi Province is taken as an example area. Four TerraSAR-X/TanDEM-X image pairs are used to carry out the interferometric calibration experiment. The results show that the elevation accuracy of all interferometric results are less than 2.54 m for this experimental data after interferometric calibration. Furthermore, the proposed method can obtain the accuracy of DEM products less than 1.21 m in the flat area and 3.11 m in the mountain area respectively.That results can prove the correctiveness and effectiveness of the proposed IPD based interferometric calibration method. The results could provide a technical basis for topographic mapping of 1∶25 000 scale in the flat area and mountain area.