UAVSAR Polarimetric

Long name Unmanned Aerial Vehicle Synthetic-Aperture Radar (UAVSAR) Polarimetric
Short name UAV
Sensor type Synthetic-aperture radar (SAR)
Platform Unmanned Aerial Vehicle (Gulfstream-III)
Frequency 1.26 GHz
Band (wavelength) L (23.79 cm)
Polarization HH, HV, VH, VV (Fully polarimetric)
Key file name (use to open data set) *.ann, *.dat
Supported file extensions *.ann, *.mlc, *.dat, *.grd, *.hgt
Data distributor

National Aeronautics and Space Administration (NASA)
NASA Jet Propulsion Laboratory (JPL)

Sections

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

Data product name and description

UAVSAR is a fully polarimetric (PolSAR) sensor mounted on and unmanned aerial vehicle (UAV) and operating at various altitudes.

Mode Swath width (km) Resolution (range x azimuth, m)* Polarization Description/notes
PolSAR ≈16

≈2.2 x 0.6 (SLC)
≈6.7 x 7.2 (MLC)
≈6.74 x 7.2 (DAT)
≈6.2 x 6.2 (GRD)

Quad (HH + HV + VH + VV) Swath width and resolution values are indicative only; values may differ significantly among data sets.

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

Processing level Acquisition mode Description/notes

Calibrated single-look complex (SLC) products
Polarimetric mode

PolSAR The projection of the data is in the natural slant-range projection. The four complex SLC files correspond to the measurement of the scattering matrix: Shh, Shv, Svh, Svv.

The units of the data are linear radar amplitude (instead of dB units).

Calibrated multi-look complex (MLC) products
Polarimetric mode

PolSAR The MLC product corresponds to a symetrized-covariance matrix derived from the average of the SLC product (typically three pixels in range, and 12 pixels in azimuth) corresponding to:
  • Three real power channels: ShhShh*, ShvShv*, SvvSvv*
  • Their complex phases: ShhShv*, ShhSvv*, ShvSvv

The projection of the data is in the natural slant-range projection. The units of the data are linear radar power (instead of dB units).

Calibrated complex cross-products projected to the ground in simple geometric coordinates (GRD)
Polarimetric mode

PolSAR The GRD files contain projected multi-looked data for cross-products: ShhShv*, ShhSvv*, ShvSvv*, ShhShh*, ShvShv*, SvvSvv* in linear power units (instead of dB).

The data is in an equiangular-coordinate system in which each line and pixel increments in latitude and longitude. Data is projected to ground range and coregistered to the height file (HGT). The HGT file contains the elevation values used to project the slant-range data to the surface of the Earth. The value of the ground elevation is provided in meters.

Compressed Stokes matrix products (DAT)
Polarimetric mode

PolSAR Compressed Stokes matrix product (.dat): AIRSAR compressed Stokes matrix format for software compatibility.

Download the PDF

One data file.

Distribution disk files

A UAVSAR PolSAR data set includes a variety of files, as described in the following table.

File name Format Required Contents/details
*.ann ASCII Yes Key file name. Annotation file. Contains metadata that applies to the data set.
*.slc Binary Yes/no Image data file.

Four of the files are complex floating-point format, 8 bytes per pixel, corresponding to the scattering matrix.

*.mlc Binary Yes/no Image data file.

Three of the files are complex floating-point format, 8 bytes per pixel, for two polarizations floating-point values (I and Q) per MLC pixel. Three of the files are real floating point, 4 bytes per pixel.

*.dat Binary Yes/no Image data file.

AIRSAR compressed Stokes matrix format.

*.grd Binary Yes/no Image data file.

The grid files consist of three real floating-point files, 4 bytes per pixel, and three complex floating-point files, 8 bytes per pixel.

*.hgt Binary Yes/no Image data file.

The height file is a pure binary real*4 floating-point file containing elevation values.

Working with UAVSAR PolSAR data

Typically, you download UAVSAR PolSAR data from the UAVSAR (NASA-JPL) website.

All of the processing levels (and associated files) may not be available for a particular data set nor is it required to download all of the available files. However, to successfully open or import a UAVSAR data set in CATALYST Professional, you must do the following:
  1. Create or open a folder in which to download all of the following files (all must be in the same folder).
  2. Download the annotation file (*.ann) of the data set.
  3. Download all the files associated with a processing level, as applicable:
    • Four single-look files (*.slc)
    • Six multi-look files (*.mlc)
    • Six grid files (*.grd)
    • Height file (*.hgt)
    • Data file (*.dat)
To open a UAVSAR data set in CATALYST Professional
  • In CATALYST Professional Focus or OrthoEngine, open the annotation file (*.ann), and then select a processing level and calibration when prompted.
To import a UAVSAR data set by running SARINGEST
  1. In EASI or Python, add one of the available data sets to the end of the annotation file (*.ann).

    For example:

    EASI> FILI = path/filename.ann-MLC

    —or—

    EASI> FILE = path/filename.ann-SLC

    —or—

    EASI> FILI = path/filename.ann-DAT

    —or—

    EASI> FILE = path/filename.ann-GRD
  2. Use the CALIBTYP parameter to specify the calibration type.

Returned data for supported format

GDB support of UAVSAR data is read-only; you cannot write imported UAVSAR data. When you open or import an available processing level by using the annotation file (*.ann), the structure of the returned data is as described in the following table.

Data product Data returned Details
Single-look complex (SLC)

4 x [C32R] Raster channels

1x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [ARR] Incidence angle array

Data calibrated in sigma nought and can also be calibrated in beta or gamma nought.

Calibrated multi-look cross-products (MLC)
Polarimetric mode

3 x [32R] Raster channels
3 x [C32R] Raster channels

1x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [ARR] Incidence angle array

Data calibrated in sigma nought and can also be calibrated in beta or gamma nought.

Calibrated complex cross-products projected to the ground in simple geographic coordinates (GRD)
Polarimetric mode

3 x [32R] Raster channels
3 x [C32R] Raster channels

1x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [ARR] Incidence angle array

Data calibrated in sigma nought.
Note: When ingesting the data, the CALIBTYPE parameter must be set to None.

Compressed Stokes matrix product (DAT)
Polarimetric mode

3 x [32R] Raster channels
3 x [C32R] Raster channels

1x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [ARR] Incidence angle array

Data calibrated in sigma nought and can also be calibrated in beta or gamma nought.

References

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