Poseidon4 on Jason-CS altimetry mission, Poseidon4 Calibration of Advanced Digital Hardware
Houpert, Alexandre1; Rys, Laurent1; Deschaux-Beaume, Marc1; Caubet, Eric1; Richard, Jacques1; Phalippou, Laurent1; Francis, Richard2; Cullen, Robert2; Koeble, Klaus-Peter3; Jaeger, Klaus3; Fornari, Marco2
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.

This new approach for on-board compression induces some evolution in the tuning, calibration and characterisation approach of the instrument, and consequently on the Level 1 ground processing approach.

This paper will present the instrument model and characterisation and calibration activities to be carried-out on the Poseidon-4 radar altimeter instrument..