轨道误差对InSAR 数据处理的影响

轨道参数是InSAR 数据处理中一个重要的参数,对从最初的图像配准到最后的高程值或形变值图像生成都有着重要的影响.含有误差的轨道参数造成基线误差以残差条纹的形式存在于干涉图中.完全去除残差条纹要求轨道绝对精度低于1mm,目前的定轨精度远不能满足要求.这里推导了轨道误差和残差干涉条纹的关系,分析了轨道误差对高程值和形变值影响的特点,提出采用二次多项式拟合的方法去除残差干涉条纹,并以巴姆地区的 ENVISAT 数据证明了提出方法的有效性.

Influence of Orbital Errors on InSAR Data Processing

Orbital state vectors,as an important parameter,which plays a crucial role in the processing of InSAR from the original offset of coarse registration to the accurate generation of the ultimate DEM or deformation measure.Errors in the baseline are caused by the errors in the orbital state vectors,which present as phase errors in the interferogram.The requirement for orbit determination would be less than 1 mm to fully correct the residual interferometric fringes,which is far below the current value around 5~10 cm.The relationship between the residual reference phase and orbit errors was built;and the influence of orbit errors played on elevation errors and deformation errors were analyzed here.And then,the quadratic polynomial approximation was proposed to eliminate residual reference phase from the interferogram,which was verified by the SAR data acquired by ENVISAT satellite over the site of the BAM earthquake.