BackForwardInstrument:  ASAR 

Instrument details
Acronym ASAR
Full name Advanced Synthetic Aperture Radar
Purpose High-resolution all-weather multi-purpose imagery for ocean, land and ice
Short description

C-band SAR, frequency 5.331 GHz, multi-polarisation and variable pointing/resolution [see detailed characteristics below]
Background

Evolution of AMI-SAR flown on ERS-1 and ERS-2
Scanning Technique

Side-looking, 15-45° off-nadir, swath 100 to 405 km, depending on operation mode - See table
Resolution 30 m to 1 km, depending on operation mode - See table
Coverage / Cycle Global coverage in 5 day for the ‘global monitoring’ mode (if used for 70 % of the time); in longer periods for other operation modes, up to 3 months
Mass 832 kg Power 1400 W Data Rate 100 Mbps

 

Providing Agency ESA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2002 to 2012
Last update: 2026-06-01
Detailed characteristics
Operation mode Resolution Swath Field of regard Polarisation

Stripmap

 30 m 100 km 485 km HH or VV

ScanSAR alternating pol

 30 m 100 km 485 km VV/HH, HH/HV, VV/VH

ScanSAR wide swath

 150 m 405 km 405 km HH or VV

ScanSAR wide swath

 150 m 405 km 405 km HH or VV

ScanSAR global monitoring

 1 km 405 km 405 km HH or VV

Wave

 30 m 5 x 5 km2 imagettes sampled at 100 km intervals HH or VV
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Earth observation instrument
  • Active and radio-occultation sensor
  • Imaging radar (SAR)
WIGOS Subcomponents
  • Subcomponent 1
  • SAR imagers and altimeters
  • SAR imager
Mission objectives
Primary mission objectives
  • Glacier cover
  • Glacier motion
  • Glacier topography
  • Ice sheet topography
  • Land surface topography
  • Sea-ice concentration
  • Sea-ice type
Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Biomass3 - highIndex only.. Infrequent coverage.C-band sensitive to total biomass
Dominant wave direction3 - highInfrequent coverage.C-band SAR. Variable measured by spectral analysis of "imagettes"
Dominant wave period3 - highInfrequent coverage.C-band SAR. Variable measured by spectral analysis of "imagettes"
Fire fractional cover3 - highInfrequent coverage.C-band SAR. High resolution, for fire boundary detection
Fraction of vegetated land4 - fairNo specific limitation.C-band SAR
Glacier cover*2 - very highLong time for mapping.C-band SAR for accurate boundary detection
Glacier motion*3 - highInfrequent coverage.C-band SAR for interferometry between images taken at time intervals
Glacier topography*3 - highLong time for mapping.C-band SAR for interferometry between images taken at time intervals
Ice sheet topography*3 - highLong time for mapping.C-band SAR for interferometry between images taken at time intervals
Land cover4 - fairNo specific limitation.C-band SAR
Land surface topography*3 - highLong time for mapping.C-band SAR for interferometry between images taken at time intervals
Oil spill cover1 - primaryInfrequent coverage.C-band SAR
Sea-ice concentration*1 - primaryNo specific limitation.C-band SAR
Sea-ice freeboard4 - fairNo specific limitation.C-band SAR. Sea ice elevation measured by interferometry
Sea-ice thickness4 - fairChange detection only.C-band SAR. Sea ice elevation measured by interferometry. Thickness inferred by ice model
Sea-ice type*2 - very highNo specific limitation.C-band SAR. Type interpreted as age/roughness
Significant wave height4 - fairHighly indirect.. Infrequent coverage.C-band SAR. Retrieved by spectral analysis of "imagettes". Boundary condition necessary for the retrieval
Snow cover3 - highThick snow only.. Infrequent coverage.C-band SAR
Snow status (wet/dry)5 - marginalThick snow only.. Infrequent coverage.C-band SAR
Snow water equivalent3 - highChange detection only.. Infrequent coverage.C-band SAR. SWE is retrieved by grigging with data from ground networks
Soil moisture (in the roots region)5 - marginalAffected by vegetation.. Infrequent coverage.C-band SAR. Assimilation process required
Soil moisture at surface3 - highAffected by vegetation.. Infrequent coverage.C-band SAR
Soil type4 - fairNo specific limitation.C-band SAR
Vegetation type5 - marginalNo specific limitation.C-band SAR
Wave directional energy frequency spectrum3 - highInfrequent coverage.C-band SAR. Variable measured by spectral analysis of "imagettes"