EO Sign In Authentication (Open): This collection is openly accessible but requires users to log in with an EO Sign In account (a system used across ESA Earth Observation services) before any downloads can proceed.

Access Steps:

1. Create or log in to EO Sign In account
2. Go to the Dissemination Service
3. Browse or search for the collection. 
4. Download product.

The dissemination service provides data generated within the ESA FDR4ALT project.

The data is collection based and allows data browsing and download via treeview, filename or advanced catalogue search.

Data download is available via HTTPS, including bulk download functionality. ESA internal users can use their ESAAD account to access the HTTPS Dissemination Service.

Access to ftps://hm-lbr-ds.eo.esa.int is available via common FTP clients using “implicit FTP over TLS” and your own EO Sign In credentials. For internal ESA users the ESAAD account cannot be used for FTP access.

This dataset is a Fundamental Data Record (FDR) resulting from the ESA FDR4ALT project.

The Fundamental Data Record for Altimetry V1 products contain Level 0 and Level 1 altimeter-related parameters including calibrated radar waveforms and supplementary instrumental parameters describing the altimeter operating status and configuration through the satellite lifetime.

The data record consists of data for the ERS-1, ERS-2 and Envisat missions for the period ranging from 1991 to 2012, and bases on the Level 1 data obtained from previous ERS REAPER and ENVISAT V3.0 reprocessing efforts incorporating new algorithms, flags, and corrections to enhance the accuracy and reliability of the data.

For many aspects, the Altimetry FDR product has improved compared to the existing individual mission datasets:

• New neural-network waveform classification, surface type classification, distance to shoreline and surface flag based on GSHHG
• Instrumental calibration information directly available in the product
• Improved Orbit solutions
• Correction of REAPER drawbacks (i.e., time jumps and negative waveforms)

The FDR4ALT products are available in NetCDF format. Free standard tools for reading NetCDF data can be used.
Information for expert altimetry users is also available in a dedicated NetCDF group within the products.

Please consult the FDR4ALT Product User Guide before using the data.

The FDR4ALT datasets represent the new reference data for the ERS/Envisat altimetry missions, superseding any previous mission data. Users are strongly encouraged to make use of these datasets for optimal results.