Radar Altimeters
type: Concept

ALT (TOPEX)
type: Concept
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]
in scheme: instruments