Converts the input synthetic aperture radar (SAR) reflectivity into physical units of normalized backscatter by normalizing the reflectivity using a reference plane.
Calibrating SAR data is necessary to obtain meaningful backscatter that can be related to the physical properties of features in the image.
Usage
For Single Look Complex (SLC) inputs, this tool will output complex data, which is composed of the real component and the imaginary component.
Use gamma nought calibration if the region of interest (ROI) does not have terrain and spans over tens of kilometers. This will ensure that the calibrated backscatter values are independent of incident angle variations. For a single SAR image, variations in gamma nought values are due to terrain and surface scattering properties.
Only use sigma nought calibration if the ROI is small and flat. For a single SAR image, variations in sigma nought values are due to incidence angle, terrain, and surface scattering properties.
This tool does not calibrate the Sentinel-1 datasets with older IPE (version 2.34 or earlier), because the calibration look-up table for these products may be incorrect.
This tool does not support a geodatabase as an output location.
Select all polarization bands if the output will be with the SAR Analysis tools.
String
Calibration Type
(Optional)
Specifies the type of calibration that will be applied.
Beta nought—The radar reflectivity will be calibrated to backscatter for a unit area on the slant range. This is the default.
Sigma nought—The backscatter returned will be calibrated to the antenna from a unit area on the ground with the plane locally tangent to the ellipsoid. This is known as the radar cross section. Sigma nought values vary due to incidence angle, wavelength, polarization, terrain, and surface scattering properties.
Gamma nought—The backscatter returned will be calibrated to the antenna from a unit area aligned with the plane perpendicular to the slant range. This normalizes gamma nought using the incidence angle relative to the ellipsoid. Gamma nought values vary due to wavelength, polarization, terrain, and surface scattering properties.
Select all polarization bands if the output will be with the SAR Analysis tools.
String
calibration_type
(Optional)
Specifies the type of calibration that will be applied.
BETA_NOUGHT—The radar reflectivity will be calibrated to backscatter for a unit area on the slant range. This is the default.
SIGMA_NOUGHT—The backscatter returned will be calibrated to the antenna from a unit area on the ground with the plane locally tangent to the ellipsoid. This is known as the radar cross section. Sigma nought values vary due to incidence angle, wavelength, polarization, terrain, and surface scattering properties.
GAMMA_NOUGHT—The backscatter returned will be calibrated to the antenna from a unit area aligned with the plane perpendicular to the slant range. This normalizes gamma nought using the incidence angle relative to the ellipsoid. Gamma nought values vary due to wavelength, polarization, terrain, and surface scattering properties.
String
Code sample
ApplyRadiometricCalibration example 1 (Python window)
This example performs the calibration using beta nought.