Odd results from Displacement analysis

s1tbx Interferometry
#1

Hi all,

I have been conducting some displacement analysis using Sentinel-1 and have been outputting bizarre / odd results, and would be very grateful if someone could advise the potential source of error.

My set-up is (apologies if this is not detailed enough):
SNAP version: 3.0
S1TBX version: 3.0.1
OS: 64-bit Windows and Centos 7 on Linux server (for SNAPHU)

I have been using the following graph process (attached):

Pasted image828×502 111 KB

20160518_InSAR_ESD_DEFOv2.xml (6.8 KB)

Everything runs without error, however, I get outputs which have a clean linear pattern (error) across the scene. Can anyone provide some insight as to why this is happening?

Pasted image1235×876 1.26 MB

Pasted image1236×881 1.34 MB

These are 24-day separated pairs with coherence between 0.8 and 0.9 and low perpendicular baselines (about 20 - 60 m)

I am confused as to:
A) Why the linear pattern from north-to-south or south-to-north? If it was in direction of the sensor I would assume look / squint angle issues.
B) What unit is the result in? I should point out I have just terrain-corrected the phase to displacement output.

Hope this makes sense, any help would be greatly appreciated!

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#2

there are atmospheric effects… you need to run SBAS or PS for accurate results.

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#3

Many thanks for your response Ben, much appreciated. Do you know if either SBAS or PS can be achieved using the Sentinel-1 Toolbox?

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#4

SNAP doesn’t do SBAS or PSI. You may want to look at StaMPS from Andy Hooper. We’re looking to have a workflow between SNAP and Stamps soon.

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