Welcome to the Harris Geospatial documentation center. Here you will find reference guides and help documents.


  >  Docs Center  >  Using ENVI  >  Calibrate to Beta Nought

ENVI

Calibrate to Beta Nought

Calibrate to Beta Nought (β0)

Use Beta Nought Calibration to radiometrically calibrate your ERS or RADARSAT data to radar brightness values (β0). The radar brightness values are output in decibels (dB). This function works for the following radar products:

  • ERS Pulse Repetition Interval (PRI)
  • RADARSAT Georeferenced Data (Level-1)
    • SAR Georeferenced Fine (SGF)
    • SAR Extra-Fine Resolution (SGX)
    • SAR Systematically Geocoded (SSG)
    • ScanSAR Narrow (SCN)
    • ScanSAR Wide (SCW)
    • Single Look Complex (SLC)

The steps for calibrating data to beta nought vary by product type.

ERS PRI Data


See ERS-1 SAR Radiometric Calibration for the method used to calibrate ERS radar data.

  1. From the Toolbox, select Radar > Beta Nought Calibration. The Select Radar Input File dialog appears.
  2. Select an ERS PRI data file and perform optional spatial subsetting, then click OK. The Beta Nought Parameters dialog appears.
  3. The ERS Incidence Angle and ERS Absolute Calibration values are automatically read from the leader file. If they are not found in the leader file, enter the center of image incidence angle and absolute calibration constant in the appropriate fields.
  4. Select output to File or Memory.
  5. Click OK.

RADARSAT-1 Data


  1. From the Toolbox, select Radar > Beta Nought Calibration. The Select Radar Input File dialog appears.
  2. ENVI reads RADARSAT-1 data in CEOS format. Select the data file (typically named dat_01.001) and perform optional spatial subsetting, then click OK. The Enter RADARSAT SAR Leader Filename dialog appears.
  3. Select a leader file (typically named lea_01.001), and click Open. The Beta Nought Parameters dialog appears.
  4. Select output to File or Memory.
  5. Click OK.

RADARSAT-2 Data


  1. From the menu bar, select File Open As > Radar Sensors > RADARSAT.

  2. The Enter RADARSAT Filenames dialog appears.

  3. Select a RADARSAT-2 image file in GeoTIFF format (image_<n>.tif, one for each polarization channel). Click Open.
  4. From the Toolbox, select Radar > Beta Nought Calibration. The Select Radar Input File dialog appears.
  5. Select the image file you just opened and perform optional spatial subsetting, then click OK. The Beta Nought Parameters dialog appears.
  6. Select output to File or Memory.
  7. Click OK.



© 2019 Harris Geospatial Solutions, Inc. |  Legal
My Account    |    Store    |    Contact Us