Poseidon4 on Jason-CS Altimetry Mission - Design and Expected Performances
Rys, Laurent1; Deschaux-Beaume, Marc1; Phalippou, Laurent1; Houpert, Alexandre1; Caubet, Eric1; Richard, Jacques1; Demeestere, Franck1; Francis, Richard2; Cullen, Robert2; Köble, Klaus-Peter3; Jaeger, Klaus3
1Thales Alenia Space, FRANCE; 2ESTEC, NETHERLANDS; 3Astrium Gmbh, GERMANY
Jason-CS, CS standing for Continuity of Service, will provide data and services to ensure continuity of the operational oceanography enabled by the Jason-1, -2 and -3 satellites (Jason-3 still being in development). Its main payload instrument is the Poseidon-4 altimeter (POS4).
The design proposed for the POS4 altimeter represents a further development step in the Poseidon product line of altimeters. These developments are both technological and functional: they provide enhanced performance and capabilities.
In terms of technology, the division between digital techniques and high-frequency analog electronics has been reassessed. The new ''Digital'' architecture takes over some previously-analog functions (with their associated tuning effort) and allows the ''deramp'' approach, introduced in SeaSat to overcome technology limitations, to revert to the more classical matched filter approach. As well as implementation advantages this has a direct effect on performance, offering increased stability and signal quality.
In terms of functionality, Poseidon-4 altimeter will embark a new mode called ''Interleaved Mode''. This last one will permit to implement SAR mode and the familiar pulse-width limited (now called Low Resolution Mode) at the same time. This offers a dramatic improvement in system capability. Full continuity with the previous Jason missions is guaranteed with the LRM, while the advantages of SAR mode in spatial resolution and particularly in the reduced height noise (by a factor of 2 or 3) will be provided in a parallel data stream.
This paper will present all of these aspects of the new Poseidon-4 altimeter.
 Optimal re-tracking of SAR altimeter echoes over open ocean: from theory to results for SIRAL2. Laurent Phalippou, Franck Demeestere. OST/ST 2011 San Diego
 Accurate numerical forward model for Optimal re-tracking of SIRAL2 SAR echoes over open ocean. Laurent Phalippou, Franck Demeestere. AGU 2011 San Francisco
 Reaching sub-centimetre range noise on Jason-CS with the Poseidon4 continuous SAR Interleaved mode. Laurent Phalippou, Eric Caubet, Franck Demeestere. 20 years of progress in radar altimetry Venice 2012.