GAMMA Questions

Hello,
You have to make the interferograms with the mosaics, not the resampled burst
SLC data.
The mosaicked SLC data should be continuous, with no gaps, and the
interferograms produced with SLC_diff_intf should be gap free...
Charles Werner

Thank you very much, I will repeat the process with giving more attention of the input datas.
Im using a workflow like:
1. preprocessing (mosaicking)of SLCs
2. creating the DEM of the AOI
3. geocoding of reference
4. coregistring of pairs with S1_coreg_TOPS
5. calculation of differential interferograms

and after that IPTA processing. Do I have to do also the deramping of the SLC-s after the coregistration, and use the deramped files for making differential interferogram?
Regards,
Ilona

You can only use deramped files for interferograms if the exactly the same
deramp has been applied to master and slave that are already coregistered!
Deramping is useful for IPTA analysis so that you can do oversampling of the
point target response. It is also useful for performing offset-tracking with
oversampling.

Thank you very much for your suggestions, it could get over the initial part of the IPTA processing.
Now I have the merged point list after the sp_stat and pwr_stat, and I'd like to move on with generating the differential interferometric phase for the point list. I've got an error at th unwrapped phase simulation. The phase_sim_orb_pt command gives me an error back, like : ERROR p_interp(): time outside of range: 17781.93488 min: 17466.24092 max: 17696.24092. How can I fix it? I attached the relevant files (0170108.rslc.par is the the geometric reference used for the co-registration)
the complete command is: phase_sim_orb_pt pt_3036613 - pSLC_par - itab - pdem psim_unw 20170108.rslc.par -
Thank you very much: Ilona

I suggest that you look at the start and stop times of the images and compare
them with the state vector start time in the SLC parameter files.
I suspect that you will find that the state vectors do not cover the start and
stop time of the images. You can see that, the min and max time are the times of
the state vector, and the time it is looking for is outside of that range. What
is the radar that you are using? Are you trying to make and interferogram for
images from different tracks? or ascending and descending? The SLC parameter
files for the particular pair that are giving the error message would be useful.
Regards,
Charles

I was looking after the time datas in the parameter files of slc-s and rslc-s also, but I cannot find any "out of time" datas (like in the error it says: 17781.93488).
I am using Sentinel datas, all of them are descending. Besides these the relative orbit is also the same for all of them.
I attach a file which contains all of the time datas of all the input datas (slc,rslc). And the first two images par file, because as I can see in the error message it stops there:

• IPTA Program phase_sim_orb_pt.c ***
• Copyright 2016, Gamma Remote Sensing, v2.0 10-Jun-2016 clw ***
• Simulate unwrapped interferometric phase (single record or all records) using orbit geometry ***
  OPENMP maximum available threads : 8
  OPENMP: setting number of theads: 4
  reading point coordinate file: pt_3036613 number of points: 3036613
  reading binary SLC parameter set: pSLC_par number of records: 8

reference SLC title: s1b-iw1-slc-vv-20170108t045244-20170108t045309-003752-006730-004.tiff S1B-IW-IW1-VV-3752 (software: Sentinel-1 IPF 002.72)
SLC range samples: 68568
SLC range looks: 1
SLC azimuth lines: 13119
SLC azimuth looks: 1
number SLCs: 8
reading ITAB file: itab number of records: 18
number of entries in the interferogram table: 18
DEM height data: pdem record: 1
geometric reference SLC parameter file: 20170108.rslc.par
SLC slant range pixel spacing (m): 2.329562
SLC azimuth pixel spacing (m): 13.935730
pulse repetition frequency (PRF) (Hz): 486.4863
Doppler centroid (Hz): -18.628
center swath incidence angle (deg.): 33.55770
SAR antenna azimuth angle (deg.): 90.0000

ITAB record: 1 SLC-1 record: 1 SLC-2 record: 2 interf.: 1 mask:1 freq_1: 5.40500e+09 freq_2: 5.40500e+09
INT: 1 SLC1: 1 SLC2: 2 jd1: 2457762 jd2: 2457774 dt: 12.000
S/C radial distance (m): 7.06922e+06 Earth radius (m): 6.36661e+06 ***************************************************************************************
0 21403.000 35.000 849885.951 849917.760 711.928 31.809 7206.667

point     pox_x      pos_y    range-1     range-2      height      delta    phase (radians)

ERROR p_interp(): time outside of range: 17781.93488 min: 17466.24092 max: 17696.24092

The start and end time of the SLC are listed in the SLC parameter files,  as is
the start time of the state vectors. The time of the last state vector is the
start time + nstate*time_interval
The time interval between state vectors is given as well as the number of state
vectors.
The stack of SLC parameter files is stored in a stack, The individual SLC
parameter files are in the same directory as the SLC images.
Cheers

The time is given in terms of seconds of day. Are all the SLCs from the same track?
why not grep the start time of all the SLCs? as well as the start time of the
state vectors.

I grepped the time, interval and number of state_vectors for the RSLCs and also for the SLC files. According to your suggested determination for the last state vector's time I cannot see any out of range time data.
The track number (relative orbit) is 51 for all of them. Is that an other way to simulate a phase for the terrain which I can later use for generating differential interferogram?
Thank you very much for your quick answers!

Hello,

Is the DEM extremely large and far outside of the bounds of the image? It might
be that in this case there is no coverage of the scene and the error occurs.
Have you sucessfully geocoded one of the scenes?  Try to figure out if it is
only one scene that is causing the difficulty.
As always, when asking a question like this we need:

1. The exact command and a copy of all the output given by the program when it
is running and the text parameter files that were used.

If we cannot determine directly what is causing the problem
2. The data files that were given as input.

phase_sim_orb-_pt is the only way to calculate the simulated phase.

Best regards,
Charles

If there is only one scene that is giving the error message, try eliminating it
from the itab and see see

Dear Charles,
Thank you very much for the instructions. As you wrote the problem was with the DEM, because it had a different dimension than the input SLC.
Regards, Ilona