Cnes (Centre National d'Etudes Spatiales)



Founded in 1961, the Centre National d'Etudes Spatiales (Cnes) is the government agency responsible for shaping and implementing France's space policy in Europe. Its task is to invent the space systems of the future, bring space technologies to maturity and guarantee France's independent access to space.
Cnes is a pivotal player in Europe's space programme, and a major source of initiatives and proposals that aim to maintain France and Europe's competitive edge.
It conceives and executes space programmes with its partners in the scientific community and industry, and is closely involved in many international cooperation programmes-the key to any far-reaching space policy.
The agency's more-than 2,400-strong workforce constitutes an exceptional pool of talent, with some 1,800 engineers and executives, 35% of whom are women.
Through its ability to innovate and its forward-looking vision, Cnes is helping to foster new technologies that will benefit society as a whole, focusing on:

  • access to space 
  • civil applications 
  • earth, environment and climate 
  • space sciences and preparing the future 
  • security and defence


AVISO is the showcase of Cnes activities in altimetry. Indeed, the altimetric products processed by the SALP service from Cnes (Service d'Altimétrie et de Localisation Précise) are distributed via AVISO portal since 1998. In recent years, AVISO has become a reference in international oceanographic and altimetric communities. In 2013, there were over 5000 registered users.
In 2014 AVISO opens to wider applications than the ocean themes. Thus becoming AVISO +, the portal opens to hydrology / coastal / ice and merges with the CTOH website to provide users with more operational and demonstration products, and expertise in an intuitive and modern web site.

Here is the new symbol of AVISO + :

  • 4 key themes (Ocean / Coast / Hydrology / Ice)
  • 2 complementary processing centers (Operational CNES / Research CTOH)
  • a shared vision and commitment to study of Earth from space and water issues, in all its forms.

Thank you to embark with us into this new adventure!

CTOH (Center for Topographic studies of the Ocean and Hydrosphere


The CTOH is a French Observation Service dedicated to satellite altimetry studies. The CTOH aims to help scientific users develop new altimetric products and applications. Within this framework, the CTOH maintains homogeneous altimetric data bases for the long-term monitoring of sea level and ocean currents, lake and river levels, the cryosphere, and the planet's climate.
The CTOH team collaborates with different scientific investigators to improve the quality of the altimetric measurements and their derived products, and to facilitate their use by scientists.
The CTOH is also an independent centre of expertise for the primary data distribution centres (AVISO for Topex/Poseidon, Jason-1 and ENVISAT in Toulouse; ESA at ESRIN, Italy, and CERSAT for ERS1/2 in Brest), and for preparing future altimetric missions.
Today, new scientific applications for altimetry are appearing : monitoring lake and river levels, the study of the continental snow and the cryosphere, flooded zones, coastal applications. The CTOH contributes to the processing and management of the altimetric data for these "emerging" research domains.
Established in 1989, the CTOH is an INSU service, supported by the Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales (Cnes), Observatoire Midi-Pyrénées (OMP), Pôle Océan-Altimétrie-Climat (CPER).

In 2014, the CTOH website is merged with the AVISO website to allow an operational product dissemination and a better visibility of the observation service within the altimetric community.


CTOH is hosted at Legos in Toulouse (France) and has an INSU label as an "observation service".