@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix ns0: <http://gcmd.gsfc.nasa.gov/kms#> .

<https://gcmd.earthdata.nasa.gov/kms/concept/fc57a9a0-a287-4bcf-a517-20811b55596b>
  skos:changeNote """2018-07-10 12:30:52.0 [mmorahan] Insert Concept 
add broader relation (Sentinel-2 MSI [fc57a9a0-a287-4bcf-a517-20811b55596b,367807] - Imaging Spectrometers/Radiometers [944b7691-af37-4fb4-9393-c114e7997829,347979]); 
""", """2018-07-10 12:34:37.0 [mmorahan]  
insert AltLabel (id: null
category: primary
text: Sentinel-2 Multispectral Imager
language code: en); 
insert Definition (id: null
text: The instrument is based on the pushbroom observation concept. The telescope features a TMA (Three Mirror Anastigmat) design with a pupil diameter of 150 mm, providing a very good imaging quality all across its wide FOV (Field of View). The equivalent swath width is 290 km. The telescope structure and the mirrors are made of silicon carbide (SiC) which allows to minimize thermoelastic deformations. The VNIR focal plane is based on monolithic CMOS (Complementary Metal Oxide Semiconductor) detectors while the SWIR focal plane is based on a MCT (Mercury Cadmium Telluride) detector hybridized on a CMOS read-out circuit. A dichroic beamsplitter provides the spectral separation of VNIR and SWIR channels.

EADS Astrium SAS of Toulouse is prime for the instrument. The industrial core team also comprises Jena Optronik (Germany), Boostec (Bazet, France), Sener and GMV (Spain), and AMOS, Belgium. The VNIR detectors are built by Astrium-E2V, while the French company Sofradir received a contract to provide the SWIR detectors for MSI.

Calibration: A combination of partial on-board calibration with a sun diffuser and vicarious calibration with ground targets is foreseen to guarantee a high quality radiometric performance. State-of-the-art lossy compression based on wavelet transform is applied to reduce the data volume. The compression ratio will be fine tuned for each spectral band to ensure that there is no significant impact on image quality.

The observation data are digitized on 12 bit. A shutter mechanism is implemented to prevent the instrument from direct viewing of the sun in orbit and from contamination during launch. The average observation time per orbit is 16.3 minutes, while the peak value is 31 minutes (duty cycle of about 16-31%).

Imager type

Pushbroom instrument

Spectral range (total of 13 bands)

0.4-2.4 µm (VNIR + SWIR)

Spectral dispersion technique

Dichroic for VNIR and SWIR split
In field separation within focal plane

Mirror dimensions of telescope

M1 = 440 mm x 190 mm
M2 = 145 mm x 118 mm
M3 = 550 mm x 285 mm

SSD (Spatial Sampling Distance)

10 m: (VNIR) B2, B3, B4, B8 (4 bands)
20 m: B5, B6, B7, B8a, B11, B12 (6 bands)
60 m: B1, B9, (3 bands)

Swath width

290 km, FOV= 20.6º

Detector technologies

Monolithic Si (VNIR); hybrid HgCdTe CMOS (SWIR)

Detector cooling

Cooling of SWIR detector to < 210 K

Data quantization

12 bit

Instrument mass, power

~ 290 kg, < 266 W

Data rate

450 Mbit/s after compression
language code: en); 
""", """2018-10-23 06:29:58.0 [mmorahan]  
insert WeightedRelation (id: null
related concept uuid: 2ce20983-98b2-40b9-bb0e-a08074fb93b3
relationship type: null
relationship value: null
generated by: null); 
""" ;
  ns0:altLabel [ ] ;
  skos:definition """The instrument is based on the pushbroom observation concept. The telescope features a TMA (Three Mirror Anastigmat) design with a pupil diameter of 150 mm, providing a very good imaging quality all across its wide FOV (Field of View). The equivalent swath width is 290 km. The telescope structure and the mirrors are made of silicon carbide (SiC) which allows to minimize thermoelastic deformations. The VNIR focal plane is based on monolithic CMOS (Complementary Metal Oxide Semiconductor) detectors while the SWIR focal plane is based on a MCT (Mercury Cadmium Telluride) detector hybridized on a CMOS read-out circuit. A dichroic beamsplitter provides the spectral separation of VNIR and SWIR channels.

EADS Astrium SAS of Toulouse is prime for the instrument. The industrial core team also comprises Jena Optronik (Germany), Boostec (Bazet, France), Sener and GMV (Spain), and AMOS, Belgium. The VNIR detectors are built by Astrium-E2V, while the French company Sofradir received a contract to provide the SWIR detectors for MSI.

Calibration: A combination of partial on-board calibration with a sun diffuser and vicarious calibration with ground targets is foreseen to guarantee a high quality radiometric performance. State-of-the-art lossy compression based on wavelet transform is applied to reduce the data volume. The compression ratio will be fine tuned for each spectral band to ensure that there is no significant impact on image quality.

The observation data are digitized on 12 bit. A shutter mechanism is implemented to prevent the instrument from direct viewing of the sun in orbit and from contamination during launch. The average observation time per orbit is 16.3 minutes, while the peak value is 31 minutes (duty cycle of about 16-31%).

Imager type

Pushbroom instrument

Spectral range (total of 13 bands)

0.4-2.4 µm (VNIR + SWIR)

Spectral dispersion technique

Dichroic for VNIR and SWIR split
In field separation within focal plane

Mirror dimensions of telescope

M1 = 440 mm x 190 mm
M2 = 145 mm x 118 mm
M3 = 550 mm x 285 mm

SSD (Spatial Sampling Distance)

10 m: (VNIR) B2, B3, B4, B8 (4 bands)
20 m: B5, B6, B7, B8a, B11, B12 (6 bands)
60 m: B1, B9, (3 bands)

Swath width

290 km, FOV= 20.6º

Detector technologies

Monolithic Si (VNIR); hybrid HgCdTe CMOS (SWIR)

Detector cooling

Cooling of SWIR detector to < 210 K

Data quantization

12 bit

Instrument mass, power

~ 290 kg, < 266 W

Data rate

450 Mbit/s after compression"""@en ;
  skos:prefLabel "Sentinel-2 MSI"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/instruments> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/944b7691-af37-4fb4-9393-c114e7997829> ;
  a skos:Concept .

<https://gcmd.earthdata.nasa.gov/kms/concept/944b7691-af37-4fb4-9393-c114e7997829>
  skos:prefLabel "Imaging Spectrometers/Radiometers"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/fc57a9a0-a287-4bcf-a517-20811b55596b> .

