基于GPS的InSAR干涉图大气效应校正方法研究

Reduction of atmospheric effects on InSAR interferograms based on GPS

大气折射延迟是InSAR测量的一个重要误差源,严重影响对干涉图的正确解译,因此必须对其进行削弱或消除,利用GPS连续运行站估计的大气天顶延迟可对干涉图中的大气效应进行校正,但离散的GPS天顶延迟须进行空间插值才能满足InSAR的高分辨率要求。本文基于天津的GPS观测数据,利用Berense、PANDA软件估算了天顶延迟,对进行了相互验证,吻合较好。通过对相隔35天的干涉图和插值后的GPS大气图比较,发现两者整体趋势上较为一致,干涉图相位去掉GPS大气延迟后,精度明显提高,长波项效应得到了有效的减弱。

The atmospheric effect is an important kind of error sources of InSAR, which influences the correct interpretation of interferograms. The atmospheric zenith delay, estimated from GPS continuous operating stations, is usually used to mitigate atmos- pheric effects on interferograms. However, for the sparse distribution, GPS zenith delay needs to be interpolated to match the high spatial resolution of InSAR. The zenith delay inferred from Berense and PANDA software over IGS stations showed high consistency. Then the restdts of Bernese and PANDA were validated and compared with each other at Tianjin region in the paper, and they agreed to each other. The interpolated GPS atmospheric delay presented similar pattern and trended to those on InSAR intefferograms. After GPS zenith delay was removed from interferograms, the accuracy of phase was clearly raised and the error of long wave length was areatlv reduced.