SAOCOM 1 A/B

Long name SAOCOM
Short name SAOC
Sensor type Synthetic-aperture radar (SAR)
Platform SAOCOM 1A, SAOCOM 1B
Frequency 1.275 GHz
Band (wavelength) L (23.513 centimeters)
Polarization HH, HV, VH, VV, RH, RV, LH, LV
Key file name (use to open data set) *.xemt
Supported file name extensions *.xml, *.tif, *.png, *.kml, *.txt
Data distributor Comision Nacional de Actividades Espaciales(Buenos Aires) and ARESYS(Milan)
Sections

Data product name and description
Distribution disk files
Returned data for supported format
References
                

Data product name and description

The acquisition modes of the SAOCOM SAR sensor are as described in the following tables.
The data can be acquired in either right or left looking configurations.
        

Note: The information provided herein is based on the SAOCOM-1 product documentation cited under References.
Mode Swath width (km) Resolution (range x azimuth, m) Polarization Description/notes

StripMap[SM]
                
Single Pol,
Dual Pol and
Compact Pol
                

31 ~ 55 depending on beam mode

10m x 5m (L1A)

10m x 10m (L1B)
                

Single Pol
HH or VV

Dual Pol
(HH + HV)
  or
(VV + VH)

Compact Pol
(RH + RV)
  or
(LH + LV)
                

There are 9 beam modes (S1-S9) with incident angles ranging from 20-50 degrees.

L1B products are multi-looked in azimuth by a factor of 2.

The image data is provided as floating point, calibrated to sigma nought in geoTIFF format with corresponding annotation files in XML format and browser PNG and KML files.

Each polarization is provided as a separate geoTIFF file.
                

StripMap[SM]

Quad Pol
                

14 ~ 29 depending on beam mode

10m x 6m(L1A)

10m x10m(L1B)
                

(HH + HV + VH + VV)

There are 10 beam modes (S1-S10) with incident angles ranging from 17-35 degrees.

L1B products are multi-looked in azimuth by a factor of 2.

The image data is provided as floating point, calibrated to sigma nought in geoTIFF format with corresponding annotation files in XML format and browser PNG and KML files.

Each polarization is provided as a separate geoTIFF file.
                

TOPSAR

Narrow [TN] Single Pol, Dual Pol and Compact Pol
                

150 ~ 176 depending on beam mode

10m x 30m(L1A)

30m x30m(L1B)
                

Single Pol
HH or VV

Dual Pol
(HH + HV)
  or
(VV + VH)

Compact Pol
(RH + RV)
  or
(LH + LV)
                

There are 2 beam modes (TNA and TNB) with incident angles ranging from 24-38 degrees for TNA and 38-47 degrees for TNB.

L1B products are multi-looked in range by a factor of 3.

The image data is provided as floating point, calibrated to sigma nought in geoTIFF format with corresponding annotation files in XML format and browser PNG and KML files.

Each polarization is provided as a separate geoTIFF file.
                

TOPSAR

Narrow [TN] Quad Pol
                

108 TNA 110 TNB

10m x 50m(L1A)

50m x50m(L1B)
                

(HH + HV + VH + VV)

There are 2 beam modes (TNA and TNB) with incident angles ranging from 17-27 degrees for TNA and 27-35 degrees for TNB.

L1B products are multi-looked in range by a factor of 5.

The image data is provided as floating point, calibrated to sigma nought in geoTIFF format with corresponding annotation files in XML format and browser PNG and KML files.

Each polarization is provided as a separate geoTIFF file.
                

TOPSAR

Wide [TW] Single Pol, Dual Pol and Compact Pol
                

354

10m x 50m(L1A)

50m x50m(L1B)
                

Single Pol
HH or VV

Dual Pol
(HH + HV)
  or
(VV + VH)

Compact Pol
(RH + RV)
  or
(LH + LV)
                

There is 1 TW beam mode with incident angles ranging from 24-49 degrees.

L1B products are multi-looked in range by a factor of 5.

The image data is provided as floating point, calibrated to sigma nought in geoTIFF format with corresponding annotation files in XML format and browser PNG and KML files.

Each polarization is provided as a separate geoTIFF file.
                

TOPSAR

Wide [TW] Quad Pol
                

218

10m x 100m(L1A)

100m x100m(L1B)
                

(HH + HV + VH + VV)

There is 1 TW beam mode with incident angles ranging from 17-35 degrees.

L1B products are multi-looked in range by a factor of 10.

The image data is provided as floating point, calibrated to sigma nought in geoTIFF format with corresponding annotation files in XML format and browser PNG and KML files.

Each polarization is provided as a separate geoTIFF file.
                

SAOCOM data sets are available for various processing levels, as described in the following table.

Processing level Acquisition mode Description/notes

L1A
Single-look, slant range, complex (SLC)
                

[SM], [TN], [TW] The SLC product is provided as complex (I and Q) values in slant range. The product is radiometrically calibrated to sigma nought without geometric corrections. The pixel spacings are constant in the slant range (X) and azimuth (Y) directions.

L1B
Multi-look, ground range, detected (GRD)
                

[SM], [TN], [TW]

The GRD product is provided as detected amplitude, reprojected to nominal ground range at zero elevation. The data is radiometrically calibrated and georeferenced.

The GRD product is a multi-look product with reduced speckle and resolution cells that are approximately square.

The pixel spacings are constant in ground range (X) and azimuth (Y) directions.
                

Distribution disk files

SAOCOM data sets (SLC, GRD) are distributed in GeoTIFF format.

Warning: Data sets for this sensor are organized in a specific folder structure on disk. GDB uses this structure and the file names to identify the data product type. Do not alter the folder structure or any file names prior to data ingestion to ensure the image data and auxiliary information are imported correctly.

File name Format Required Contents/details
*.xemt Extensible Markup Language Yes Key file name. Main product annotation file.
*.xml Extensible Markup Language Yes Schema and description of metadata
*.tif GeoTIFF Yes Image data. One GeoTIFF file per polarization. (DATA folder)
*.png Portable network graphic No Thumbnail of image (IMAGE folder)
*.kml Keyhole Markup Language No Google Earth Overlay (IMAGE folder)

Returned data for supported format

SAOCOM data can be opened directly in its raw vendor format or imported into a PCIDSK (*.pix) file using the key file (*.xemt). For optimal processing, use the PCIDSK format.

In the following table, the data structure after it is imported into a PCIDSK file is described (supported processing levels only).

Data product Data returned Details

L1A
(single pol)

StripMap [SM]
TOPSAR Narrow [TN]
TOPSAR Wide [TW]
                  


                  1 x [C32R] raster channel (calibrated to sigma nought)
                  1 x [TEX] main product annotation
                  1 x [BIN] rational function model from state vectors
                  1 x [ARR] incidence angle array
                

Data can be converted to beta, or gamma nought.

L1A
(dual and compact pol)

StripMap [SM]
TOPSAR Narrow [TN]
TOPSAR Wide [TW]
                


                  2 x [C32R] raster channel (calibrated to sigma nought)
                  1 x [TEX] main product annotation
                  1 x [BIN] rational function model from state vectors
                  1 x [ARR] incidence angle array
                

Data can be converted to beta, or gamma nought.

L1A
(quad pol)

StripMap [SM]
TOPSAR Narrow [TN]
TOPSAR Wide [TW]
                


                  4 x [32R] raster channel (calibrated to sigma nought)
                  1 x [TEX] product annotatio
                  1 x [BIN] rational function model from state vectors
                  1 x [ARR] incidence angle array
                

Data can be converted to beta, or gamma nought.

L1B
(single pol)

StripMap [SM]
TOPSAR Narrow [TN]
TOPSAR Wide [TW]
                


                  1 x [32R] raster channel (calibrated to sigma nought)
                  1 x [TEX] product annotation
                  1 x [BIN] rational function model from state vectors
                  1 x [ARR] incidence angle array
                

Data can be converted to beta, or gamma nought.

L1B
(dual and compact pol)

StripMap [SM]
TOPSAR Narrow [TN]
TOPSAR Wide [TW]
                


                  2 x [32R] raster channel (calibrated to sigma nought)
                  1 x [TEX] product annotation
                  1 x [BIN] rational function model from state vectors
                  1 x [ARR] incidence angle array
                

Data can be converted to beta, or gamma nought.

L1B
(quad pol)

StripMap [SM]
TOPSAR Narrow [TN]
TOPSAR Wide [TW]
                


                  4 x [32R] raster channel (calibrated to sigma nought)
                  1 x [TEX] product annotation
                  1 x [BIN] rational function model from state vectors
                  1 x [ARR] incidence angle array from
                

Data can be converted to beta, or gamma nought.

References

[1] Ministerio de Ciencia, Tenologia e Innovacion,(CONAE), SAOCOM-1 Level-1 Products Format, January 13, 2020

[2] Geotiff specification http://www.alternatiff.com/resources/TIFF6.pdf

[3] GeoTIFF Format Specification GeoTIFF Revision 1 http://geotiff.maptools.org/spec/geotiffhome.html

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