Performances study of interferometric radar altimeters: from the instrument to the global mission definition
Vivien Enjolras(1) , Patrick VINCENT(2) , Jean-Claude SOUYRIS(1) , Anny Cazenave(3) , Ernesto RODRIGUEZ(4) , Bruno CUGNY(1) , and Laurent PHALIPPOU(5)
18, av. Edouard Belin,
(2) IFREMER, 155 rue Jean Jacques Rousseau, 92138 ISSY LES MOULINEAUX, France
(3) LEGOS, 14, av. Edouard Belin, 31400 Toulouse, France
(4) Jet Propulsion Laboratory, 4800 Oak Grove Drive, PASADENA, CA, 91109, United States
(5) ALCATEL SPACE, 26, av. Jean Francois Champollion, 31000 Toulouse, France
The main limitations of standard nadir-looking radar altimeters have been known for long. They include the lack of coverage (intertrack distance of typically 150 km for the T/P and Jason tandem), and the spatial resolution (typically 2 km for T/P and Jason), expected to be a limiting factor first for both the determination of mesoscale phenomena in the deep ocean, and then for coastal and large basins hydrological applications.
In this context, a new and revolutionnary altimetric measurement has been assessed for the past few years. Mixing altimetry and interferometry, it increases by almost a hundred times the observation swath and aims to keep a typical measurement error budget about a few centimetres to catch most of the ocean circulation. The Wide Swath Ocean Altimeter (WSOA) was primarily expected to be implemented onboard Jason-2 satellite. A global study of the performances of this instrument and its interactions with any external factors was driven by CNES (Centre National d'Etudes Spatiales) in cooperation with NASA/JPL since end of 2003. Every error domain has been checked and the outcomes have led to the definition of a dedicated mission to such an instrument.
Keywords: altimetry, interferometry, error budget, system analysis, ocean, mesoscale