GEMSAR: DLR's project for the generation of global digital elevation
Noack, Richard Bamler, Michael Eineder, Achim Roth, Hartmut Runge
Forschungsanstalt fuer Luft- und Raumfahrt Oberpfaffenhofen, Deutsches
Fernerkundungsdatenzentrum, D-82234 Wessling, Phone: +49-8153-28-1390,
knowledge of terrain height is an indespensable prerequisite of remote
sensing applications e.g. for the interpretation of SAR data from mountaineous
and hilly terrain. The usage of currently available digital elevation models
(DEMs) is handicapped by a number of reasons: they are not global, not
homogeneous, the resolution is not adequate and they are expensive.
The conventional approach for generating DEM's is to use stereo cameras
or digitized maps. For the past ten years techniques applying interferometric
SARs (INSAR) have been developed, e.g. the ERS tandem data are a new and
operational source for the generation of DEM's.
DLR has been receiving ERS tandem data at its Neustrelitz receiving
station. However, the most important source of interferometric SAR data
in the future will be the SRTM (Shuttle Radar Topography Mission) carrying
a modified SIR-C? X-SAR instrument used as a single pass interferometer:
the SIR-C C-band SCANSAR will deliver a global and homogeneous DEM of all
landmasses between 60 deg. north and 60 deg. south, and in parallel X-SAR
will deliver regional DEMs of high resolution. SRTM will be launched in
May 2000 on a two-week shuttle mission.
Therefore, within the GEMSAR (Global Elevation Models from SAR) project
algorithms will be developed for the generation of interferograms from
ERS tandem, X-SAR and SIR-C data, including automatic phase unwrapping
and mosaicking of continent wide DEMs. The systems to be built up comprise
SAR processors, interferogram generators and DEM generators.
The DEMs will be archived in a growing DEM data base and will be
made available through a user interface which allows for the specification
of arbitrarily shaped areas, resolutions and cartographic representations.
This data base will be capable of storing DEMs from different sensors,
including optical sensors.
INSAR, DEM, GEMSAR, SRTM, X-SAR
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,