NATIONAL REPORT OF THE FEDERAL REPUBLIC OF ... - IAG Office

Introduction
Various space missions are in preparation or have already
been launched to minor bodies as comets, planets and their
moons. Here, geodetic applications and techniques play an
ever increasing role. Most of the missions include cameras
for imaging the planetary surface or the atmosphere in
different spectral wavelengths. Image processing and photogrammetry
provide fundamental technologies and analysis
algorithms. Moreover, X-rays are also used for spectroscopic
mapping of the geological structures of the bodies.
Recently, laser altimetry is getting more and more important
in planetary science. Altimeter observations can be used
for generating topographic or geological maps, and, in combination
with gravimetric data, for determining the longwavelength
gravity field.
One of the first applications in planetary science was Lunar
Laser Ranging (LLR). Observations have continuously been
taken since the early 70ies. LLR provides one of the
longest, non-interrupted space-geodetic time-series.
Lunar Laser Ranging
Lunar Laser Ranging data analysis allows the determination
of many quantities of the Earth-Moon dynamics like the
Moon’s orbit and gravity field, Earth orientation, or the
selenocentric and terrestrial reference frames. Most beneficial
is the determination of numerous relativistic parameters
like the equivalence principle or the time-variation
of the gravitational constant. Lunar Laser Ranging observations
of about 36 years have been analysed by KOCH (2005),
MÜLLER et al. (2006a; 2006b).
Besides the data analyses, LLR shall also be supported by
new German range measurements. Therefore the German
Fundamental Station Wettzell will be renewed, so that LLR
measurements can be expected in the near future. The
contribution of LLR for geodetic applications and its
visibility shall further be improved by J. Müller (IfE) who
serves as LLR representative in the ILRS Governing Board
and as ILRS representative in the Directing Board of the
International Earth Rotation and Reference Systems Service
(IERS) since 2006. More information on recent achievements
of LLR is given in the section on “Space Geodetic
Techniques (VLBI, LLR, SLR, DORIS)”.
ICC on Planetary Geodesy (ICCPG)
CH. KOCH 1 , J. MÜLLER 2
1 Christian Koch: Max-Planck-Institute for Solar System Research, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany,
Tel. +49 - 5556 - 979 - 408, Fax +49 - 5556 - 979 - 240, e-mail koch@mps.mpg.de
2 Jürgen Müller: Institut für Erdmessung (IfE), Leibniz Universität, Hannover, Schneiderberg 50, 30167 Hannover, Germany,
Tel. +49 - 511- 762-3362, Fax +49 - 511 - 762-4006, e-mail mueller@ife.uni-hannover.de
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Image processing / photogrammetry / spectroscopy
Most of the results related to ‘planetary ’ image processing
in Germany are related to the HRSC-camera onboard Mars
Express. ALBERTZ et al. (2005) discuss the photogrammetric
background of this camera. GEHRKE et al. (2003; 2006)
present mapping results. GWINNER et al. (2005) and LEH-
MANN et al. (2005) address the determination of large scale
digital terrain model. GIESE et al. (2005) present maps of
Phobos, ROATSCH et al. (2006) topographic maps of
Saturn’s icy moons. KELLER et al. (2005; 2007) describe
the OSIRIS camera onboard the Rosetta mission developed
for mapping the comet’s surface. The camera was also used
during the Deep Impact mission to the comet Tempel 1.
Further photogrammetric data processing in the planetary
context is, e.g., discussed in OBERST et al. (2003) and
SCHOLTEN et al. (2004; 2005b). The application of spectroscopy
for retrieving geological maps of the bodies’ surfaces
and their composition is presented, e.g., by BASILEVSKY
et al. (2004).
Laser altimetry
Laser altimetry is quite a new field in planetary science.
Laser altimeters are adopted, e.g., for the MESSENGER
or BepiColombo missions. Laser altimeters can be used in
planetary science very well because of the different structure
and composition of the planets' atmosphere – compared
to that of the Earth. Their atmosphere is less dense for
investigations in the generally used wavelength of laser
altimeters of 1064 nm. Those observations can be analysed
to generate topographic or geological maps and to determine
time-dependent variations of the quantities of interest.
A laser altimeter was applied, e.g., onboard the Mars
Express mission for mapping the surface topography.
Another mission planned for Mercury is the BepiColombo
mission (OBERST et al. 2006). From a scientific perspective,
laser altimeter data sets provide several additional information
for retrieving slopes or reflectivity of the surfaces at
the chosen laser wavelengths.