The Radar Observing System for Europe at L-band (ROSE-L) is part of the Copernicus Expansion Programme which focuses on new missions that have been identified by the European Commission (EC) as priorities for implementation in the coming years. ROSE-L provides additional capabilities above and beyond those of the current Sentinel missions, filling observation gaps as well new and emerging user needs not yet addressed.
ROSE-L is a user driven mission. By filling important observation gaps in the current Copernicus satellite constellation, the ROSE-L mission supports key European policy objectives and provides enhanced continuity for a number of Copernicus services and down-stream commercial and institutional users. Due to the longer wavelength, L-Band SAR observations from space provide additional information that cannot be gathered by other means benefiting a variety of services and applications.
A high-level mapping between specific European policy objectives and the unique information provided by the mission is provided below. The mission will contribute inter alia to:
- The safety of European Citizens by greatly extending the monitoring of geohazards linked with surface motion such as landslides, subsidence and earthquake/volcanic phenomena into vegetated areas which are inaccessible to current Copernicus satellites and will be critical to the nascent European Ground Motion Service (EU-GMS);
- The European Arctic policy and the sustainable economic development of the Arctic region by providing new information sea ice types and detection of icebergs critical to safe navigation and building of infrastructure in Arctic areas;
- Forestry and maintaining biodiversity through the continuous high-resolution monitoring of changes in global forest carbon stocks and their spatial distribution;
- Agriculture and food security by providing reliable high-resolution soil moisture information to support improved management of water use, enhances weather-independent land cover and crop information, feeding meteorological and hydrological forecast models;
- EU Water Framework Directive through mapping of water availability and water use particularly for agriculture;
- Climate change policy through the enhanced monitoring of glaciers and ice sheets, forest carbon stocks and changes with time and water availability;
- The European Union Integrated Maritime Policy by extending the capacity to monitor our marine ecosystem and by increasing our maritime surveillance abilities.
- Line-of-sight surface motion addressing deformation measurements, urban subsidence, landslides, flooding
- Forest above ground biomass, forest area, forest change, land cover maps, crop type and status products to support Land use, Land use change, forestry and agriculture
- Soil moisture at regional and global scale to support improved weather forecasts, hydrology and water management
- Sea ice type, sea ice concentration, sea ice motion, glacier/ice cap surface velocity, grounding line and snow water equivalent (SWE) in support of Cryosphere and Arctic application needs
- Wind and wave spectrum information over oceans for regular forecast, EMR and extreme events
- Vessel detection oil spill mapping and ice berg detection in support of maritime security
The requirements and implementation of the ROSE-L SAR mission cannot be considered in isolation but need to build on existing and planned Copernicus observation capabilities and new commercial/NewSpace SAR developments to derive maximum benefits for users and services. Observational gaps filled by ROSE-L requires careful combination of the new information with information provided by existing Sentinel missions. The enhanced continuity also requires harmonised, coordinated and systematic acquisitions in conjunction with other Sentinel data, and in particular those provided by the C-band radar aboard Sentinel-1.
The ROSE-L SAR instrument will operate in L-band, i.e. in the frequency range from 1.215 to 1.300 GHz. The L-band SAR instrument will be able to operate in SAR modes suitable for imaging land and coastal areas, as well as sea-ice and open ocean. Derived from the high-level mission objectives, the SAR instrument of the ROSE-L mission is currently based on three main imaging modes:
- Dual-polarisation (co- and cross-polarisation)
- Wave Mode.
The dual- polarisation mode represents the nominal “work-horse” imaging mode of ROSE-L, to enable systematic imaging over global land and ice, with a focus on Europe. It combines a large swath with high resolution and high quality imaging specifications e.g. -28 dB NESZ. This mode meets most user requirements in the various application areas supported by the ROSE-L mission. By selecting a main mode of operation, conflicting requests from users and corresponding gaps in acquisitions are avoided and a consistent and complete archive of data to support long-term assessments of trends is secured.
ROSE-L is implemented as a 3-axis stabilized satellite based on the new Thales Alenia Space Multi-Mission Platform product line (MILA) and will embark the L-Band Synthetic Aperture Radar (SAR) Instrument dedicated to the day-and-night monitoring of land, ice and oceans offering improved revisit time, full polarimetry, high spatial resolution, high sensitivity, low ambiguity ratios and capability for repeat-pass and single-pass cross-track interferometry. It is based on a 5-panel deployable 11 m × 3.6 m L-Band, highly innovative and lightweight planar Phased Array Antenna (PAA). The satellite will also carry a set of three Monitoring Cameras (CAM) to monitor the deployment of the SAR antenna and the solar arrays.