The multimission processing of altimeter data was developed by CLS as part of Duacs (Developing Use of Altimetry for Climate Studies), a European Commission 3-year project which started in February 1997. Duacs was a shared cost project, part-funded under the CEO Programme of the Environment and Climate.
 
Since the end of the original project, the near real time (NRT) and delayed time (DT) components have continued to serve operational oceanography and climate forecasting projects. The system has been redesigned and significantly upgraded as the knowledge of altimetry processing was refined and as the oceanography needs evolved. Renamed with the same acronym (Data Unification and Altimeter Combination System), it had been integrated to the Cnes multi-mission ground segment Ssalto in 2001, and it was maintained, upgraded and operated with funding from Cnes with shared costs from EU projects till May 2015. The data had been distributed through Aviso from 2003.
 
From May 2015 on, the Copernicus Marine and Environment Monitoring Service (EU http://marine.copernicus.eu/) is taking over the whole processing, the operational production and distribution of level-3 and 4 data.
 
Duacs demonstrated that altimeter data can be processed in near real time with sufficient accuracy to help improve the skill of climate simulations. The multi-mission products developed for the original Duacs project are now widely used in the scientific community. They cover a large spectrum of operational oceanography needs, from mesoscale to climate applications.