BackForwardInstrument:  SAR-C (RISAT) 

Instrument details
Acronym SAR-C (RISAT)
Full name Synthetic Aperture Radar (C-band)
Purpose High-resolution all-weather multi-purpose imager for ocean, land and ice
Short description C-band SAR, frequency 5.35 GHz, variable pointing/resolution [see detailed characteristics below]
Background New development
Scanning Technique Side-looking, possible both to left- and right- hands (alternatively) 20-49° off-nadir, swath 10 to 220 km, depending on operation mode - See table
Resolution 1 m to 50 m, depending on operation mode - See table
Coverage / Cycle Near-global coverage in 1 month for the wide-swath mode (assuming duty cycle 30 %); longer periods for other operation modes; shorter (down to 1 week) on selected areas by strategic pointing
Mass 950 kg Power 3100 W Data Rate 1478 Mbps (maximum)

 

Providing Agency ISRO
Instrument Maturity Backed by strong heritage
Utilization Period: 2012 to 2029
Last update: 2021-06-15
Detailed characteristics

 

Operation mode

Resolution

Swath

Field of regard

Polarisation

HRS (High Resolution Spotlight)

 1 m

10 km

659 km, either right or left

HH or VV or HH/HV or VV/VH

FRS-1 (Fine Resolution Stripmap-1)

3 m

30 km

659 km, either right or left

HH or VV or HH/HV or VV/VH

FRS-2 (Fine Resolution Stripmap-2)

9 m

30 km

659 km, either right or left

VV/HH, HH/HV, VV/VH

MRS (Medium Resolution ScanSAR)

25 m

120 km

659 km, either right or left

HH or VV or HH/HV or VV/VH

CRS (Coarse Resolution ScanSAR)

50 m

240 km

659 km, either right or left

HH or VV or HH/HV or VV/VH
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 cover
  • 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
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"
Sea-ice cover*1 - primaryNo specific limitation.C-band SAR
Sea-ice elevation4 - 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