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. DUACS demonstrated that altimeter data can be processed both in Delayed time (DT) and in near-real time (NRT) with sufficient accuracy to help improve the skill of climate simulations.
Since the end of the original project, the NRT and 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 to 2017.
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 of different altimeter sea level measurements.
The DUACS multi-mission products are now widely used. They cover a large spectrum of operational oceanography needs, from mesoscale to climate applications.