News - Success Stories

How Envisat helped to shape global understanding of Earth’s systems

Twenty years have passed since a ground-breaking European spacecraft designed to deliver unprecedented insight into the planet’s changing environment was lofted into orbit.

Activity - Projects

Dragon 2 Cooperation Programme

The Dragon 2 Programme focussed on the exploitation of ESA, ESA's Third Party Missions and Chinese Earth observation data for science and applications development in land, ocean and atmospheric applications.

News - Data Release news

Release of new Envisat DORIS Precise Orbit data

A new version of the Envisat Precise Orbit products has been generated by the Centre de Traitement Doris Poseidon (CTDP) using the Geophysical Data Records F standards (GDR-F). The new dataset (DOR_VOR_AX vF) is now available to users in Envisat format from the ESA dissemination service.

Tools - Apps

Heritage Missions app for Android

Download the Heritage Missions application to discover what the missions were about, how it worked and what the elements of the space and ground segment that make these missions unique.

Document - Product Specifications

Envisat products specifications - Volume 9 - DORIS products specifications

Data - Fast Registration with immediate access (Open)

ERS PRARE Precise Orbit Product (ERS.ORB.POD/ERS.ORB/PRC)

The precise orbit results from a data reduction process in which all available tracking data (Single-Lens Reflex, radar altimeter crossovers, PRARE range and Doppler data) and most accurate correction, transformation and dynamical models are taken into account and in which high level numerical procedures are applied. These orbits are "optimal" achievable representations of the real orbital motion under the circumstances of tracking situation and the "state of the art" model situation. The precise orbit product for the ERS satellites are the satellite ephemeris (position and velocity vector) including time tag, given in a well-defined reference frame, together with the nominal satellite attitude information and a radial orbit correction. Several orbit solutions are currently distributed: A new set of ORB POD (Precise Orbit Determination - REAPER v2) computed with the most updated model standards for the complete ERS-1 and ERS-2 mission. A previous set of ORB POD (REAPER v1) data already available on the ESA dissemination site since 2014, covering the ERS-1 full mission and the ERS-2 mission up to July 2003. ORB PRC which is the original Precise Orbit dataset computed during the ERS mission operations for ERS-1 and ERS-2. In the new POD dataset (REAPER v2) for the ERS-1 and ERS-2 missions, two different orbit solutions are provided together with the combined solution to be used for processing of the radar altimeter measurements and the determination of geodetic/geophysical products: those computed by DEOS (Delft Institute of Earth Observation and Space Systems), and those generated by ESOC (European Space Operations Centre) using different software (GEODYN and NAPEOS respectively). Careful evaluation of the various solutions of REAPER v2 has shown that the DEOS solution for both ERS-1 and ERS-2 has the best performance and is recommended to be used as reference. See the ERS Orbit Validation Report. For the previous version of the POD data set (REAPER v1), with ERS-2 mission data only up to 2003, three different orbit solutions together with the combined solution are available. These precise orbits for ERS-1 and ERS-2 have been computed at DEOS, ESOC, and GFZ (Deutschen GeoForschungsZentrums) using different software and different altimeter databases. Combined solutions have been created using three individual solutions for each satellite. All orbits were derived using consistent models in the same LPOD2005 terrestrial reference frame. These new orbit solutions show notable improvement with respect to DGME04 orbits (Scharroo and Visser, 1998). Thus, RMS crossover differences of new orbits improved by 4-9 mm. Careful evaluation of the various solutions has shown that the combined solution for both ERS-1 and ERS-2 has the best performance. All POD orbit files (REAPER v1/v2) are available in SP3c format.

Data - Fast Registration with immediate access (Open)

Envisat DORIS Doppler [DOR_DOP_1P]

This product was generated by the Centre de Traitement Doris Poseidon (CTDP). The DORIS Doppler product (DOR_DOP_1P) was consolidated offline 2-4 weeks after sensing and stored in the F-PAC archive. The file size is 0.5 Mbytes per orbit.

Data - Fast Registration with immediate access (Open)

Envisat DORIS Precise Orbit [DOR_VOR_AX]

The latest version of the Envisat DORIS Precise Orbit product, DOR_VOR_AX, was generated by the Centre de Traitement Doris Poseidon (CTDP) using the Geophysical Data Records F standards (GDR-F). The product is used to obtain the satellite orbital parameters (latitude, longitude, height and height rate) by using orbit computation routines. The most significant changes related to the GDR-F standards concern the new ocean tide model (FES2014) and the updated Terrestrial Reference Frame (ITRF2014). The new standards significantly improve all Precise Orbit Determination (POD) metrics with respect to GDR-E. The mean difference and variance of Sea Surface Height (SSH) at crossovers is slightly reduced. The DOR_VOR_AX product adopts the Envisat format, and the size is 0.2 Mbytes per orbit. Users are recommended to apply the GDR-F version, but the previous datasets are still available (i.e. GDR-D and GDR-E versions). See further details in the readme file for Envisat DORIS Precise Orbit Determination files. Comparison of Envisat Sea Level Anomaly trends obtained using DORIS Precise Orbit GDR-E and F standards. North/South patterns are evident. Credits: CNES/CLS.

Mission - Heritage Missions

Envisat

Envisat was ESA's successor to ERS. Envisat carried ten instruments aboard for a wide range of Earth observing fields. The mission was operational from 2002 to 2012.

News - Data Release news

Updated Precise Orbit data (POD) for the full ERS-1 and ERS-2 mission available

The Precise Orbit files (ERS.ORB.POD) for the entire ERS-1 and ERS-2 mission periods have been reprocessed with up-to-date standards.

Document - General Reference

BIOMASS-Report-for-Mission-Selection-An-Earth-Explorer-to-observe-forest-biomass.pdf

The objective of the BIOMASS Mission is to determine the global distribution of forest biomass by reducing the uncertainty in the calculation of carbon stock and fluxes associated with the terrestrial biosphere.

Document - General Reference

TIGER Initiative - Looking After Water in Africa

This brochure presents images from the second TIGER Workshop, held in Pretoria from 08 to 10 November 2004. The images show locations in Africa acquired by Meteosat-8, Envisat's ASAR and MERIS instruments and Proba-1's HRC instrument.

Document - General Reference

Envisat-The-Future.pdf

This brochure provides an overview of the Envisat mission.

Document - General Reference

ERS-Radar-data-for-operational-land-cover-mapping-AfriCover-Study.pdf

This report illustrates the results obtained during the ESA-ESRIN/FAO Pilot Study conducted within the Remote Sensing Exploitation Department of ESA/ESRIN by Gianna Calabresi and Juerg Lichtenegger, with contributions from Jarkko Koskinen, presently with the Helsinki University of Technology, Finland.

Document - General Reference

Farewell-to-ERS2.pdf

This is an article extracted from the ESA Bulletin Nr.148.

Document - General Reference

Healing-the-Earth-Earth-Observation-Supporting-International-Environmental Conventions.pdf

This article is extracted from ESA Bulletin Nr. 128.

Document - General Reference

Happy-Birthday-ERS-1991-2001.pdf

This brochure celebrates the tenth anniversary of the ERS mission. ERS-1 was launched in 1991 and was joined by ERS-2 in 1995.

Document - General Reference

The four Candidate Earth Explorer Core Missions - Land-Surface Processes and Interactions Mission

This report describes the Land-Surface Processes and Interactions Mission, one of the four Candidate Earth Explorers in 1999.

Document - General Reference

The Earth Observation Handbook, 2010 Update - Key Tables

This is the 2010 update of the CEOS Earth Observation Handbook. You can browse the live database at http://database.eohandbook.com/ or download the printable PDF of key tables based on the 2010 database contents for a handy reference.

Document - Product Cal/Val Plan/Report

ERS-2-Rapid-Products-Validation.pdf

This note shortly summarizes the validation activities for the new rapid orbit and altimeter products RPD/ROPR for ERS-2. Besides internal quality measures the products are compared with the operational Preliminary Orbit (PRL) and the Quick-Look Ocean Product Records (QLOPR).