Radar altimetry by satellite is a technique used in oceanography to measure, globally over the oceans, the sea level needed to understand ocean circulation and its variability.

The AltiKa project developed by CNES is based on alarge Ka-band altimeter (35.75 GHz, 500MHz), 1st oceanographic altimeter using such a high frequency. The use of the Ka-band frequency will supply more accurate measurements (improvement of the spatial and vertical resolution) enabling a better observation of ices, coastal areas, continental water bodies as well as the waves height.

The AltiKa project is part of the operational satellite altimetry system, jointly with Jason-2, and enables to ensure the service continuity which is nowadays provided by Envisat altimeter jointly with Jason-2 and Jason-1.

By ensuring the observations continuity and widening the observation areas, CNES answers the wish of the oceanography community by bringing a description:

for the meso-scale in open ocean,
in coastal areas,
for the seasonal forecast,
for the climate studies.

AltiKa data will thus contribute, along with data from others altimetry missions, to the development of operational oceanography, to our climate understanding and to the development of forecasting capabilities through data assimilation methods improvement in coupled ocean-atmosphere coupling models, bio-chemistry models, etc.

The high resolution altimeter AltiKa integrates a bi-frequency radiometric function enabling to correct the altimetric measurements from wet troposphere effects. AltiKa is coupled with the precise orbitography system, DORIS, associated to a laser reflector, in order to determine accurately the satellite position on its orbit.

With ARGOS-3 mission instruments, the whole AltiKa payload will be set on board SARAL satellite, developed in cooperation with ISRO (indian Space Agency) which provides the platform and ensures the prime contractorship of the satellite, its launch and the control/command operations. CNES provides the payload AltiKa and ensures the data reception and processing by using SALP services (Service d'Altimetrie et de Localisation Precise). Two other processing centres process AltiKa data: EUMETSAT for the realtime, ISRO for the real and delayed-time data. Saral Satellite launch is scheduled for summer 2012.