Fundamental Data Records for Altimetry (FDR4ALT) is an ESA project aiming at generating innovative Earth system data records named Fundamental Data Records (basically level 1 altimeter and radiometer data) and Thematic Data Records (basically level 2P geophysical products), in the frame of the European Long Term Data Preservation Program (LTDP+).

These products will be based on the exploitation of measurements acquired by the altimeter and radiometer instruments onboard three remote sensing satellites, ERS-1, ERS-2 and ENVISAT.

The goal is to serve the different communities involved in long term data exploitation over the different Earth surfaces: ocean, coastal, inland water, ice sheets, sea ice and atmosphere.