BackForwardInstrument:  SAR-X (RISAT-2) 

Instrument details
Acronym SAR-X (RISAT-2)
Full name Synthetic Aperture Radar (X-band)
Purpose High-resolution all-weather multi-purpose imager for ocean, land and ice. Most useful for recognisance
Short description X-band SAR, frequency 9.59 GHz, multi-polarisation and variable swath/resolution [see detailed characteristics below]
Background New development
Scanning Technique Side-looking, 20 to 45 degrees, swath 10 to 50 km, depending on operation mode, addressable within a field-of-regard of 650 km, either right or left – See table
Resolution 1 to 8 m, depending on operation mode - See table
Coverage / Cycle Determined by strategic pointing (within 650 km). Minimum revisit time for a selected location: 5 d
Mass Power Data Rate

 

Providing Agency ISA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2009 to 2025
Last update: 2024-01-23
Detailed characteristics

Operation mode

Resolution

Swath

Field of regard

Polarisation

Super-Stripmap

1.8 m

10 km

650 km, either right or left

HH or VV or HV or VH

Stripmap

3 m

10 km

650 km, either right or left

HH or VV or HV or VH

ScanSAR

8 m

50 km

650 km, either right or left

HH or VV or HV or VH

Spotlight

2 m

10 km

650 km either left or right

HH or VV or HV or 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
  • Fraction of vegetated land
  • Glacier motion
  • Glacier topography
  • Land cover
  • Land surface topography
  • Soil moisture at surface
  • Soil type
  • Vegetation 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
Dominant wave direction2 - very highInfrequent coverage.X-band SAR. Variable measured by spectral analysis of "imagettes"
Dominant wave period2 - very highInfrequent coverage.X-band SAR. Variable measured by spectral analysis of "imagettes"
Fire fractional cover3 - highInfrequent coverage.X-band SAR. High resolution, for fire boundary detection
Fraction of vegetated land*3 - highNo specific limitation.X-band SAR
Glacier cover2 - very highLong time for mapping.X-band SAR for accurate boundary detection
Glacier motion*5 - marginalInfrequent coverage.X-band SAR for interferometry between images taken at time intervals
Glacier topography*3 - highLong time for mapping.X-band SAR for interferometry between images taken at time intervals
Land cover*3 - highNo specific limitation.X-band SAR
Land surface topography*3 - highLong time for mapping.X-band SAR for interferometry between images taken at time intervals
Oil spill cover1 - primaryInfrequent coverage.X-band SAR
Significant wave height3 - highHighly indirect.. Infrequent coverage.X-band SAR. Retrieved by spectral analysis of "imagettes". Boundary condition necessary for the retrieval
Snow cover3 - highThick snow only.. Infrequent coverage.X-band SAR
Snow status (wet/dry)4 - fairThick snow only.. Infrequent coverage.X-band SAR
Snow water equivalent3 - highChange detection only.. Infrequent coverage.X-band SAR. SWE is retrieved by grigging with data from ground networks
Soil moisture at surface*3 - highStrongly affected by vegetation.. Infrequent coverage.X-band SAR
Soil type*3 - highNo specific limitation.X-band SAR
Vegetation type*5 - marginalNo specific limitation.X-band SAR
Wave directional energy frequency spectrum2 - very highInfrequent coverage.X-band SAR. Variable measured by spectral analysis of "imagettes"