Help Content > Interferometry Module > Interferometric Tools

Purpose

Displacement Decomposition tool calculates the vertical, east-west and optionally north-south components of the displacement. For 2D decomposition more than one DInSAR displacements measurements are needed over the same area of interest. For 3D decomposition (2D+1D, 1D+2D) more than two DInSAR displacements measurements are needed over the same area of interest.

Technical Note

This tool exploits displacement measurements obtained from different acquisition geometries to retrieve the displacement components along east-west, vertical and optionally north-south. This tool can deal with geocoded DInSAR displacement only (in raster format).

Results from different sensor are supported.

Minimum input data requirements for 2D decomposition options are:

- 1 Ascending and 1 Descending geometry measurements ;

- 2 Ascending or 2 Descending (with at least a difference of 10° incidence angle between the Line of Sight of the input geometries, as for example, near-range and far-range over the same area of interest).

Minimum input data requirements for 3D (2D+1D Theoretical: north component is derived from theoretical assumptions, its accuracy is lower than the east-west and vertical component) decomposition options are:

- 1 Ascending and 2 Descending geometry measurements;

- 2 Ascending and 1 Descending geometry measurements;

- >1 Ascending and >1 Descending (with at least a difference of 10° incidence angle among the Line of Sight of the input geometries, as for example, near-range, medium-range and far-range over the same area of interest), best option.

Minimum input data requirements for 3D (1D+2D) decomposition options are (north component accuracy is lower than the east-west and vertical component):

- 1 Multi-Aperture Interferometry/Amplitude tracking along satellite flight direction measurement, 1 Ascending and 1 Descending geometry measurements;

- 1 Multi-Aperture Interferometry/Amplitude tracking along satellite flight direction measurements, 2 Ascending or 2 Descending geometry measurements (with at least a difference of 10° incidence angle between the Line of Sight of the input geometries, as for example, near-range, medium-range and far-range over the same area of interest).

In order to obtain a more reliable decomposition result, a higher number of input are suggested, since the decomposition kernel applies a weighted least-square inversion. The weights are derived from the LOS displacement precision.

Please note: _ALOS, _ILOS, _precision, _dem ancillary files have to be in the same folder specified for the requested input _disp file (measured displacement generated by the DInSAR, MAI, Amplitude tracking processing).

Sign convention:

vertical direction: positive values upward, negative values downward;

east-west direction: positive values eastward, negative values westward;

north-south direction: positive value northward, negative value southward.

Please note: the north-south component accuracy is limited due to the geometrical acquisition of SAR data, with respect to east-west and vertical direction

Basic input DInSAR measurement configuration for 2D decomposition (figure 1 below).

Optional higher redundancy input DInSAR measurement configuration for 2D and 3D decomposition (figure 2 below).

Each displacement measure is fully described by the magnitude and the angles (azimuth and inclination) of the satellite Line Of Sight.

Input Files

File name of the displacement file (_disp, _velocity_geo). This file is mandatory (please, refer to technical notes).

Principal Parameters

Displacements Decomposition Type

The options for DInSAR displacement decomposition are:

•Decomposition 2D, decomposition in vertical and east-west directions.

•Decomposition 2D+1D (Theoretical), decomposition in vertical and east-west directions (2D), and north-south direction (1D).

•Decomposition 1D+2D, decomposition in vertical (1D), and east-west and north-south directions (2D); in case of availability of Multi-Aperture Interferometry/Amplitude tracking along satellite flight direction measurement.

Output Files

Output Root Name

Name of the output root. This file is mandatory.

_decomposed_east_disp

Displacement component along the East-West direction.

_decomposed_vertical_disp

Displacement component along the vertical direction.

_decomposed_north_disp

Displacement component along the north-south direction.

_decomposed_east_Dprecision

Displacement precision component along the East-West direction.

_decomposed_vertical_Dprecision

Displacement precision component along the vertical direction.

_decomposed_north_Dprecision

Displacement precision component along the north-south direction.

_DEM

Weighted average DEM combination.

_inXXALOS

Input ALOS file.

_inXXILOS

Input ILOS file.

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.

The window will be closed.

Help

Specific help document section.

Specific Function(s)

None.