Title :
Off-nadir radar altimetry
Author :
Parsons, Chester L. ; Walsh, Edward J.
Author_Institution :
NASA Goddard Space Flight Center, Wallops Island, VA, USA
fDate :
3/1/1989 12:00:00 AM
Abstract :
The characteristics of nadir versus off-nadir altimetry are reviewed and contrasted and a potentially serious problem has been pointed out that has been overlooked by earlier investigators, who focused on the nongeophysical error sources in off-nadir altimetry. Spatial gradients of radar cross section on the sea surface, caused by wind or current gradients or the variation of radar cross section with incidence angle, could introduce significant range errors in off-nadir altimeter. This potentially crippling effect can be overcome by leaving the traditional 13-GHz frequency and implementing the multibeam altimeter at 36 GHz. A multibeam altimeter proposed for the Eos (Earth Observing System) is described as well as a multimode airborne radar altimeter being developed to study problems inherent in off-nadir altimetry
Keywords :
height measurement; oceanographic equipment; oceanographic techniques; radar applications; radar cross-sections; radioaltimeters; remote sensing; 36 GHz; EHF; Earth Observing System; Eos; MARA; current gradients; errors; incidence angle; multibeam altimeter; multimode airborne radar altimeter; nadir altimetry; oceanographic techniques; off-nadir altimetry; radar altimetry; radar cross section; remote sensing; sea surface; wind; Altimetry; Earth Observing System; Instruments; NASA; Radar remote sensing; Satellites; Sea surface; Space technology; Spaceborne radar; Surface topography;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
