GECOS

Starting point / motivation

Current synthetic aperture radar (SAR) satellite missions, such as the Sentinel-1 satellite constellation of the European Copernicus Programme, are a key element of the global satellite Earth Observation system. Repeat-pass SAR interferometry (InSAR) is a main application tool of SAR missions, used for mapping and monitoring surface motion and deformation with high precision and spatial detail.

However, repeat-pass InSAR suffers from temporal decorrelation of the interferometric phase, causing a critical gap in observation capabilities for geohazard events, volcanic outbreaks and downwasting of ice bodies. This deficit can be overcome by single-pass interferometric SAR (SP-InSAR) formations as these are not subject to temporal decorrelation.

The German TanDEM-X mission has demonstrated the great value of SP-InSAR, strongly motivating the development and implementation of an SP-InSAR formation linked to an operational SAR mission to provide extended capabilities in terms of temporal and spatial coverage. To this end the Sentinel-1 SAR companion Multistatic Explorer (SESAME) mission was proposed in response to the ESA Call for Proposals for Earth Explorer Mission EE-9.

SESAME features two receive-only C-band radar (passive SAR) satellites flying in close formation to build a single-pass SAR interferometer which uses the active signal of Sentinel-1. Members of the GECOS project team have been actively involved in elaboration of the science plan for SESAME.

Contents and goals

The proposed GECOS project aims at further advancing and testing tools and applications of C-band SP-InSAR for geosphere monitoring and research.

The project will focus on the following applications: 

• in cryosphere and climate research: monitoring the temporal change of volume and mass of glaciers and ice caps;
• in geohazard monitoring: the detection and mapping of displaced volumes of active landslides, debris flows, lava flows and volcanic eruptions;
• in geodynamics and geotechnics: mapping of surface deformation and its temporal evolution.

Methods

During the first project phase the goals for geosphere monitoring applications of a C-band SAR companion satellite flying in formation with an operational SAR mission will be defined and observational requirements for geophysical products will be specified. Taking into account these requirements, methods and software for generating products on surface topography, topographic change, and surface deformation will be elaborated, with focus on use of interferometric C-band single-pass and repeat-pass SAR systems.

The software will be applied for generating InSAR products from data of current and past SAR missions for application studies. InSAR-based products on surface elevation and elevation change will be produced for demonstrating and validating applications in glacier mass balance monitoring and for detecting and quantifying displaced volumes of landslides and volcanic deposits. Products on surface deformation and its temporal evolution will be generated for evaluating applications over unstable ground and sedimentary basins.

Expected results

The project will deliver updated information on observational and technical requirements for a C-band SP-InSAR constellation, deliver data sets for demonstrating innovative applications, and provide performance estimates for geophysical products.

The project developments and results will be exploited for updating specifications for a future passive C-band SAR companion satellite, for consolidating performance estimates for geophysical products, and for promoting key applications.

Coordinator

ENVEO Environmental Earth Observation Information Technology GmbH

Project partner

• AIT Austrian Institute of Technology GmbH, Energy Department Environmental Resources and Technologies
• Joanneum Research, DIGITAL - Institute for Information and Communication Technologies / Remote Sensing and Geoinformation

ENVEO Environmental Earth Observation Information Technology GmbH
Dr. Thomas Nagler
Technikerstrasse 21a
A-6020 Innsbruck