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

<https://gcmd.earthdata.nasa.gov/kms/concept/fee5e9e1-10f1-4f14-94bc-c287f8e2c209>
  ns0:altLabel [ ] ;
  skos:definition """[Source: SMAP home page Instrument Description, http://smap.jpl.nasa.gov/instrument/ ]

The SMAP instrument architecture incorporates an L-band radar and an L-band radiometer that share a single feedhorn and parabolic mesh reflector. The reflector is offset from nadir and rotates about the nadir axis at 14.6 rpm, providing a conically scanning antenna beam with a surface incidence angle of approximately 40°. The reflector has a diameter of 6 m, providing a radiometer footprint of 40 km. The real-aperture radar footprint is 30 km, defined by the two-way antenna beamwidth.

To obtain the desired high spatial resolution the radar employs range and Doppler discrimination. The radar data can be processed to yield resolution enhancement to 1-3 km spatial resolution.
 
The science goal is to combine the attributes of the radar and radiometer observations in terms of their spatial resolution and sensitivity to soil moisture, surface roughness, and vegetation. Soil moisture will be estimated optimally at a resolution of 10 km and freeze-thaw state at a resolution of 1-3 km. 

The provision of constant incidence angle across the 1000-km swath simplifies the data processing and enables accurate repeat-pass estimation of soil moisture and freeze/thaw change.  


Group: Instrument_Details
   Entry_ID: SMAP L-BAND RADIOMETER 
   Group: Instrument_Identification
      Instrument_Category: Earth Remote Sensing Instruments
      Instrument_Class: Passive Remote Sensing
      Instrument_Type: Spectrometers/Radiometers
      Instrument_Subtype: Imaging Spectrometers/Radiometers
      Short_Name: SMAP L-BAND RADIOMETER
      Long_Name: SMAP L-Band Radiometer
   End_Group
   Group: Instrument_Associated_Sensors
      Short_Name: SMAP L-BAND RADAR
   End_Group
   Group: Associated_Platforms
      Short_Name: SMAP
   End_Group
   Group: Spectral_Frequency_Information
      Spectral_Frequency_Coverage_Range: 1.41 GHz
   End_Group
   Online_Resource: http://smap.jpl.nasa.gov/instrument/
   Online_Resource: http://nasascience.nasa.gov/missions/smap
   Online_Resource: http://eospso.gsfc.nasa.gov/eos_homepage/mission_profiles/show_mission.php?id=72
   Creation_Date: 2009-09-23
   Group: Instrument_Logistics
      Instrument_Owner: USA/NASA
   End_Group
End_Group"""@en ;
  skos:prefLabel "SMAP L-BAND RADIOMETER"@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/fee5e9e1-10f1-4f14-94bc-c287f8e2c209> .