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Purpose

 

This functionality enables to execute the orbital refinement and phase re-flattening process for all pairs at once. This step is mandatory.

 

Technical Note

The Interferogram Refinement and Re-flattening is a mandatory step. A Ground Control Point file (i.e. "Orbital GCP file") must be previously generated; the points must be located onto the Super Master image geometry (typically the _fint or _upha files are the best products for the GCP location). It is suggested to use the "Residual Phase" option (Preferences>Flattening>Refinement and Re-flattening>Refinement Method) in order to make the system more robust.

The Ground Control Points in the "Orbital GCP file" are selected with the same criteria and for the same purpose of the Ground Control Points used in the Refinement and Re-flattening step. Note that the criteria for the GCPs selection must be fulfilled for all possible (or most of them) interferometric pairs. As result of this processing step, the re-flattened  unwrapped phases (_reflat_upha) and the re-flattened filtered interferograms (_reflat_fint) are written in the "interferogram_stacking", “interf_tiff” subfolder; and in the "work_interferogram_stacking" subfolder. The "IS_reflat_upha_list_meta" and the "IS_reflat_fint_list_meta", are both generated with the link the re-flattened products.

From this step onwards, it is possible to move the entire SBAS_processing folder in another disk location without causing any problem in the further steps.

Input Files

 

Auxiliary file

Reference file generated as output of the "Connection Graph" step and possibly updated afterwards. This file is mandatory.

 

Refinement GCP file

Either a previously created Ground Control Point file (.xml) is loaded (Load GCP File) or the interface to create a new Ground Control Point file is automatically loaded ( Create GCP File, refer to the "Tools>Generate Ground Control Point" for details).

 

DEM/Cartographic System

 

Digital Elevation Model file

Name of the Digital Elevation Model file. This should be referred to the ellipsoid. This file is optional. In case it is omitted, the ellipsoidal height and the relevant cartographic reference system, must be entered.

 

Output Projection

In case that the Digital Elevation Model is not used, the following parameters are compulsory to define the Cartographic System:

 

State

Definition of the country or general projection systems.

 

Projection

Definition of the projection system of the selected State. In case that a general projection system is selected in State, the Projection is automatically set.

 

Ellipsoid

Definition of the ellipsoid. This is chosen according to the selected State and Projection.

 

Hemisphere

Definition of the hemisphere. This is chosen according to the selected State and Projection.

 

Zone

Definition of the zone. This is chosen according to the selected State and Projection.

 

Datum Shift Parameters

Definition of the datum shift parameters. These are chosen according to the selected State and Projection.

 

Reference Height

In case that the Digital Elevation Model is not used, a constant ellipsoidal height must be provided. Default Reference Height is 0.

 

Cartographic Parameters

The reference parameters for some projection systems (e.g. Stereographic, Polar Stereographic, Gnomonic, Mercator, Miller, Albers, etc.) can be set.

 

Parameters - Principal Parameters

 

Rebuild All

By setting this flag the whole process is started from scratch. It is advisable to leave this flag unchecked in case of process interruption, so that the products already generated have not to be computed and stored again.

Coregistration with DEM

By setting this flag, the input Digital Elevation Model is used in the co-registration process.

Refinement method

The choice is given between the following refinement methods:

•Automatic Refinement.

•Polynomial Refinement.

•Orbital Refinement.

Refer to the flattening section of the Preferences for further information about these methods.

 

 

Rebuild All

By setting this flag the whole process is started from scratch.

 

It is advisable to leave this flag unchecked in case of process interruption, so that the products already generated have not to be computed and stored again.

 

Coregistration with DEM        

By setting this flag, the input Digital Elevation Model is used in the coregistration process.

 

Refinement method

The choice is given between the following refinement methods:

 

•Automatic Refinement;

 

•Polynomial Refinement;

 

•Orbital Refinement.

 

Refer to the flattening section of the Preferences for further information about these methods.

 

Refinement Residual Phase Polynomial Degree

Degree of the polynomial used to estimate the phase ramp, which will be removed from the input unwrapped phase during the Re-flattening operation. In case this value is higher that the number of input Ground Control Points, it will be automatically decreased. The default values of 3 means that a phase ramp in range and azimuth direction plus a constant phase offset will be corrected. In case only the phase offset correction is needed, the polynomial degree will be set to 1.

Parameters - Global

 

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Parameters - Flattening

 

It brings to the flattening section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Parameters - Interferogram
 

It brings to the interferometry section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Parameters - Refinement

 

It brings to the  flattening section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Parameters - Coregistration

 

It brings to the co-registration section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Parameters - Other Parameters

 

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

 

Output Files

 

interferogram_stacking folder

Directory containing the following products:

•Due to the large number of output products meta (_meta). and series (.series).files are generated. They enable to load at once all relevant output products:

•The “interf_tiff” sub-folder with the tiff files of intermediate interferometric SBAS results.

•The internal copy of the input refinement and re-flattening GCP (.xml).

•The input refinement and re-flattening GCP converted in shape format in slant geometry (.shp).

•The input refinement and re-flattening GCP converted in shape format in geocoded geometry (.shp and .kml).

Generated meta and series files:

•FI_reflat_fint_meta, which refers to all re-flattened and filtered interferograms. 

•FI_reflat_upha_meta, which refers to all re-flattened unwrapped phases. Note that this same extension is used for the 2nd level unwrapped products, which are generated during the SBAS Inversion step.

work_interferogram_stacking folder

Directory used to store intermediate processing results.

 

Details specific to the Units of Measure and Nomenclature of the output products can be found in the Data Format section.

 

 

General Functions

 

Exec

The processing step is executed.

 

Store Batch        

The processing step is stored in the batch list. The Batch Browser button allows to load the batch processing list.

 

Close        

The window will be closed.

 

Help

Specific help document section.

 

 

Specific Function(s)

 

None.        

 

References

None