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Instrument Overview

Mosaic of different RA results
Mosaic of different RA results

The Radar Altimeter (RA) onboard the ERS-1 and ERS-2 missions was a Ku-band (13.8 GHz) nadir-pointing active microwave sensor designed to measure the time return echoes from ocean and ice surfaces. Functioning in one of two operational modes (ocean or ice) the RA provided information on significant wave height; surface wind speed; sea surface elevation, which relates to ocean currents, the surface geoid and tides; and various parameters over sea ice and ice sheets.

The ERS-1 mission launched on 17 July 1991 and ended on 10 March 2000. ERS-2 was launched on 21 April 1995 and retired on 5 September 2011.


Data Description

The full mission reprocessing of the ESA ERS Radar Altimetry (RA) Level 2 data has been completed and the dataset is available online to the ESA Earth Observation user community. REAPER (REprocessing of Altimeter Products for ERS) covers both the ERS-1 and the ERS-2 Altimetry missions. The reprocessed dataset spans from the start of the ERS-1 mission in July 1991 to June 2003, when the loss of the ERS-2 on-board data storage capability occurred causing the end of the ERS-2 global mission coverage.

All RA (ERS) products, in accordance with ESA Earth Observation Data Policy, are freely available to registered users via FTP. Read more about the available products and the registration process which is required to access them:

Data Tools

Atmospheric Toolbox

The Atmospheric Toolbox (also known as BEAT) is a collection of executable tools and an application programming interface (API) which has been developed to facilitate the utilisation, viewing and processing of ESA GOMOS, MIPAS, SCIAMACHY and GOME data.



The Broadview Radar Altimetry Tutorial and Toolbox is an online tutorial containing an extensive explanation on what is altimetry, the techniques used and examples of usage of altimetry data in several different fields of research.


Sentinel-1 Toolbox

The Sentinel-1 Toolbox consists of a collection of processing tools, data product readers and writers and a display and analysis application to support the large archive of data from ESA SAR missions including ERS and Envisat, as well as Third Party SAR data from ALOS, TerraSAR-X, COSMO-SkyMed and RADARSAT-2..


Sentinel-3 Toolbox

The Sentinel-3 Toolbox consists of a rich set of visualisation, analysis and processing tools for the exploitation of data from the Sentinel-3 mission. As a multi-mission remote sensing toolbox, it also supports the ESA missions Envisat, ERS, SMOS as well as Third Party data from Aqua and Terra, Landsat, ALOS and others.



The HEDAVI (HEritage DAta Visualisation) service enables users to discover a wealth of heritage data from ESA's ERS and Envisat missions, as well as from Landsat-5 and Landsat-7, two important heritage Third Party missions at ESA, through ESA's heritage data programme ‘LTDP'.



The goal of RA (ERS) calibration and validation activities was to verify the accuracy and quality of data the instrument acquired. RA (ERS) Validation documents are available.

Quality Control Reports

Quality Control is monitoring routinely the status of the spacecraft (payload and platform) and to check if the derived products meet the quality requirements along mission life-time. RA (ERS) Cyclic Reports are available.



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