天绘二号双星InSAR成像与DSM生成技术

Bistatic InSAR interferometry imaging and DSM generation for TH-2

天绘二号是编队飞行的双卫星合成孔径雷达系统,相比于传统InSAR系统,它能够消除时间和大气等去相干源,产生高相干性的SAR图像对。本文首先阐述了基于双曲等效的双星干涉扩展线性调频变标(extended chirp scaling, ECS)成像处理算法,并引入预滤波处理混合基线带来的相干性降低和干涉相位误差等问题。然后介绍了双星模式下干涉处理方法和三维重建的技术流程。最后用天绘二号某试验场山地区域的原始回波数据进行了干涉成像试验,并用生成的SAR图像对进行三维重建,分析了图像的相干性,相位解缠结果与DSM重建结果。试验结果验证了本文的干涉成像算法具有良好聚焦性和保相性,同时验证了数据的干涉测量和三维重建能力。

TH-2 is a bistatic synthetic aperture radar(SAR) satellite system in formation flight. Compared with traditional InSAR systems, it can eliminate decoherent sources such as time and atmosphere, besides, it can generate highly coherent SAR image pairs. This paper firstly describe the extended chirp scaling(ECS) imaging algorithm based on the hyperbolic equivalent method, and also introduces pre-filtering to deal with problems such as reduced coherence and interference phase errors caused by mixed baselines. Secondly, it introduces the interference processing method and the technical process of DSM reconstruction in the bistatic mode. Finally, an interference imaging experiment is performed using the original echo data of a certain mountainous experimental area, and the 3 D reconstruction experiment is performed by using the generated SAR image pair, which analyzes the coherence of the image, the phase unwrapping results and the DSM reconstruction results. The experimental results verify that the interference imaging algorithm in this paper has good focusing effect and phase preservation capacity. At the same time, the interferometry and 3 D reconstruction capabilities of the data are verified as well.