RADARGRAMMETRY AS A TOOL FOR GEOSCIENTIFIC APPLICATIONS
M. F. Buchroithner and G. Triebnig
Institute for Image Processing and Computer Graphics
Graz Research Center, Austria
ABSTRACT
The usefulness of air- and spaceborne synthetic
aperture radar (SAR) imagery for geoscientific applications
can be improved by integration of various radargrammetric
processing methods. Radar images display ground range
non-linearity and along-track skewness induced by radar
mapping characteristics and residual SAR system biases which
affect both the geometric and radiometric quality of the
data.
This paper discusses some of the tasks to be
accomplished for georeferencing of SAR images. It
emphasizes some of the aspects important for map-to-image
correspondence and deseribes methods employing digital
geocoding algorithms for the rectification of a SAR image to
the geometry of a three-dimensional map. The geocoding
algorithms are based on bundle adjustment restitution of
ephemeris data’ or, ‘alternatively, “on a technique for
registration of real SAR data onto synthesized SAR images
generated from a digital terrain model.
Generation of synthesized SAR imagery by simulating
radar projection and target response allows systematic
investigations into problems of land feature extraction and
radar stereoscopy. Results from recent studies in these
fields are addressed, and aspects of SAR image quality
dependent on imaging geometry, such as information loss due
to foreshortening, layover and shadow are touched.
1. INTRODUCTION
Synthetic aperture radar (SAR) has matured to become
one of the operational means of air- and spaceborne remote
sensing data acquisition. Its independence on ambient
illumination and weather, and its particular sensitivity to
roughness and dielectric properties of the earth's surface
make SAR especially attractive for geomorphology and earth
resources applications. Mapping of geological features,
forested areas and land use as well as monitoring of
agricultural crops, snow cover, land and sea ice are typical
tasks where SAR data can favourably be utilized.
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