@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/c45c4e30-e253-4329-8838-8991a53f494f>
  ns0:altLabel [ ] ;
  skos:definition """[Source: GFZ/Potsdam, http://www.gfz-potsdam.de/ ]

The Star Camera Assembly (SCA) (also called Star Camera System or SCS) will be manufactured (as for CHAMP) by the Danish University of Technology (DUT) and is used for the precise orientation of the satellite within the AOCS and for the correct interpretation of the ACC measurements. The SCA consists of 2 simultaneously operated DTU star cameras with a field of view of 18° by 16° and one Data Processing Unit (DPU). It will measure the S/C's attitude better than 0.3 mrad (with a goal of 0.1 mrad) by autonomous detection of star constellations using an onboard available star catalogue. The SCA is rigily attached to the accelerometer and views the sky at 45° angle with respect to the zenith at the port and starboard sides. In the case that the sun will move into the field of view of one of two sensors the second sensor will proceed to measure the attitude. To avoid velocity induced aberration the SCA is equipped with an orbit propagator which will be regularily updated by the  GPS navigation solution.


Group: Instrument_Details
   Entry_ID: GRACE SCA
   Group: Instrument_Identification
      Instrument_Category: Earth Remote Sensing Instruments
      Instrument_Class: Passive Remote Sensing
      Instrument_Type: Photon/Optical Detectors
      Instrument_Subtype: Cameras
      Short_Name: GRACE SCA
      Long_Name: Star Camera System
   End_Group
   Group: Associated_Platforms
      Short_Name: GRACE
   End_Group
   Group: Spectral_Frequency_Information
      Wavelength_Keyword: Visible
   End_Group
   Online_Resource: http://www.csr.utexas.edu/grace/spacecraft/sis.html#sis2
   Online_Resource: http://www.gfz-potsdam.de/portal/
   Creation_Date: 2009-08-14
   Group: Instrument_Logistics
      Instrument_Owner: USA/NASA
   End_Group
End_Group"""@en ;
  skos:prefLabel "SCS"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/instruments> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/d322ae9d-bde0-448f-948d-777aef096eb6> ;
  a skos:Concept .

<https://gcmd.earthdata.nasa.gov/kms/concept/d322ae9d-bde0-448f-948d-777aef096eb6>
  skos:prefLabel "Cameras"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/c45c4e30-e253-4329-8838-8991a53f494f> .