Figure 4: Part of Ida image s0202561900 (66m ground
pixel size)
may be generated using images with different spectral fil-
ters. What is more, precise photometric corrections will be
possible, as the incidence and emittence angles of sunlight
on the surface which are a prerequisite for the utilization of
photometric functions, may be determined from the high
resolution DTM. This will allow us to perform more precise
spectral studies of the asteroid.
3 SUMMARY AND OUTLOOK
In this paper the photogrammetric processing of digital
SSI images of asteroid Ida is described. The results of
the photogrammetric processing comprise a ground con-
trol network and a DTM covering one hemisphere of Ida.
The control net consists of 96 points with an (interior) ac-
curacy of 180 m. Based on the control net and on 7,300
ground points derived from digital image matching a 1?x 1?
DTM was obtained. The D'TM represents the global sur-
face characteristics quite well, as verified by comparison
with the images.
Goals of future investigations are
e to improve the rotation parameters of Ida,
e to determine the ephemeris of Ida's moon Dactyl,
e to improve the DTM by shape-from-shading tech-
niques,
e to apply the developed methods to Galileo SSI im-
ages of Jupiter's satellites
4 ACKNOWLEDGEMENTS
In performing this study we received valuable support
by Jürgen Oberst and Bernd Giese at the Institute of
Planetary Exploration of the DLR, which is gratefully ac-
knowledged. Part of the work presented in this paper is
624
funded by grant 50 QM 9205 of the German Space Agency
(DARA).
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