@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/ab172a97-a1ed-4a5b-ba0b-8b39685b76a5>
  ns0:altLabel [ ] ;
  skos:definition """TOPEX Altimeter Sensor/Instrument:

The TOPEX altimeter is a dual frequency radar instrument which draws
upon a long heritage of single-frequency altimeters extending back to
Seasat. The primary channel for the altimeter is Ku-band (13.6 GHz),
and the secondary channel is C-band (5.3 GHz). Inclusion of the
secondary channel allows correction for propagation delays in the
ionosphere, reducing a significant error source in the measurement.

The ALT was developed and built by the Applied Physics Laboratory of
the John Hopkins University (APL/JHU) under contract to the Wallops
Flight Facility of NASA's Goddard Space Flight Center (GSFC) on behalf
of JPL.

      Additional information available at
      "http://podaac.jpl.nasa.gov:2031/SENSOR_DOCS/topex_alt.html"

      [Summary provided by NASA]"""@en ;
  skos:prefLabel "ALT (TOPEX)"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/instruments> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/92ddaaca-40b2-4936-bc1a-28cc5743e8b8> ;
  a skos:Concept .

<https://gcmd.earthdata.nasa.gov/kms/concept/92ddaaca-40b2-4936-bc1a-28cc5743e8b8>
  skos:prefLabel "Radar Altimeters"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/ab172a97-a1ed-4a5b-ba0b-8b39685b76a5> .