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Instrument: 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:
2012-10-19 to 2017-03-31
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
Mission objectives
Primary mission objectives Glacier cover Glacier motion Glacier topography Ice sheet topography Land surface topography Sea-ice cover Sea-ice type
Secondary mission objectives Dominant wave direction Dominant wave period Fraction of vegetated land Land cover Oil spill cover Snow cover Snow status (wet/dry) Snow water equivalent Soil moisture at surface Wave directional energy frequency spectrum
Opportunity objectives Biomass Fire fractional cover Sea-ice elevation Sea-ice thickness Significant wave height Soil moisture (in the roots region) Soil type Vegetation type Show all Show fewer
Tentative 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
Variable Relevance for measuring this variable Operational limitations Explanation
Biomass 3 - high Index only.. Infrequent coverage. C-band sensitive to total biomass
Dominant wave direction 3 - high Infrequent coverage. C-band SAR. Variable measured by spectral analysis of "imagettes"
Dominant wave period 3 - high Infrequent coverage. C-band SAR. Variable measured by spectral analysis of "imagettes"
Fire fractional cover 3 - high Infrequent coverage. C-band SAR. High resolution, for fire boundary detection
Fraction of vegetated land 4 - fair No specific limitation. C-band SAR
Glacier cover 2 - very high Long time for mapping. C-band SAR for accurate boundary detection
Glacier motion 3 - high Infrequent coverage. C-band SAR for interferometry between images taken at time intervals
Glacier topography 3 - high Long time for mapping. C-band SAR for interferometry between images taken at time intervals
Ice sheet topography 3 - high Long time for mapping. C-band SAR for interferometry between images taken at time intervals
Land cover 4 - fair No specific limitation. C-band SAR
Land surface topography 3 - high Long time for mapping. C-band SAR for interferometry between images taken at time intervals
Oil spill cover 1 - primary Infrequent coverage. C-band SAR
Sea-ice cover 1 - primary No specific limitation. C-band SAR
Sea-ice elevation 4 - fair No specific limitation. C-band SAR. Sea ice elevation measured by interferometry
Sea-ice thickness 4 - fair Change detection only. C-band SAR. Sea ice elevation measured by interferometry. Thickness inferred by ice model
Sea-ice type 2 - very high No specific limitation. C-band SAR. Type interpreted as age/roughness
Significant wave height 4 - fair Highly indirect.. Infrequent coverage. C-band SAR. Retrieved by spectral analysis of "imagettes". Boundary condition necessary for the retrieval
Snow cover 3 - high Thick snow only.. Infrequent coverage. C-band SAR
Snow status (wet/dry) 5 - marginal Thick snow only.. Infrequent coverage. C-band SAR
Snow water equivalent 3 - high Change detection only.. Infrequent coverage. C-band SAR. SWE is retrieved by grigging with data from ground networks
Soil moisture (in the roots region) 5 - marginal Affected by vegetation.. Infrequent coverage. C-band SAR. Assimilation process required
Soil moisture at surface 3 - high Affected by vegetation.. Infrequent coverage. C-band SAR
Soil type 4 - fair No specific limitation. C-band SAR
Vegetation type 5 - marginal No specific limitation. C-band SAR
Wave directional energy frequency spectrum 3 - high Infrequent coverage. C-band SAR. Variable measured by spectral analysis of "imagettes"