GACOS for PSInSAR
interferogram dates stored as a matrix with name ifgday and size [n_ifgs 2]. The master image is in the first and slave in the second column respectively. Specify dates a numeric value in YYYYMMDD format.
gacos_datapath =  The full path to your GACOS processing folder.
UTC_sat = [‘HH:MM’] The UTC time of the satellite pass over your study area. It is specified as a string in a two digit hour and two digit minute format “HH:MM”. A colon needs to be included in between!
demfile = [pwd ‘dummy.dem’]
or = [pwd ‘dummy.grd’] The path to the DEM_file. Few options are included: 1) using a “.grd” file, 2) a DEM_file with corresponding DEM_file.rsc file, 3) a DEM file with DEM_file xml file (isce-like). For option 2 the DEM_file.rsc should contain the associated WIDTH, LENGTH, X_STEP (resolution), Y_STEP(-1*resolution), X_FIRST and Y_FIRST (upper left corner of the DEM), and optional the FORMAT. X and Y refer to longitude and latitude. You can use construct_dem.sh to make you DEM file.
ll_matfile = [pwd ‘ll.mat’] Full file path of the geo-coordinates, stored in
a matrix with size [n_points 2] and in its
columns the longitude and latitude.
Those parameters are from TRAIN manual. Those directories I still need how to find and/or create because I was only using Train’s default APS linear correction that doesn’t require any auxiliary data other than the exported products from snap’s automated pre-processing. I have requested GACOS zenith total delay ZTD maps for the same date and time of Sentinel-1 acquisition which I use for snap-to-stamps processing but I am not sure how to apply the correction using those delay maps.
So, I was hoping if anyone could help me identify what those data that are required for GACOS atmospheric correction and set up TRAIN to apply that correction during/after StaMPS processing