Error of DInSAR interferogram

Hello everyone
DATA: S1A_IW_SLC__1SSV_20150912T012217_20150912T012244_007675_00AA76_08F2


orbit:precise orbit
SNAP sentinel-toolbox version 2.02

I use these data to make an interferogram, to be obvious, there are some huge fringe. But there’s no surface modification. so there shouln’t have fringe. Perhapse these fringe are caused by orbit error, but i used precise orbit.
can anyone give me some advice?

thanks a lot!!

Based on the rugged terrain in area where you scene was taken, those fringes are due to topology. To remove the topographic phase, find a function Topographic Phase Removal in SNAP.

Hi jegrix
I had removed the Topographic Phase befor filter, that’s why i have some confusion about this phenomenon.