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LOCAL, REGIONAL AND GLOBAL POINT DETERMINATION USING THREE-LINE IMAGERY
AND ORBITAL CONSTRAINTS
Timm Ohlhof
Chair for Photogrammetry and Remote Sensing
Technical University Munich, Germany
Phone: +49-89-2105 2671, Fax: +49-89-280 95 73
E-Mail: timm@photo.verm.tu-muenchen.de
Commision III, Working Group 1
KEY WORDS: Orientation, Simulation, CCD, Extraterrestrial, Three-Line, Bundle Block Adjustment, Orbital Con-
straints, MOMS-02
ABSTRACT
The emphasis of that paper is point determination using spaceborne 3-line imagery and orbital constraints. In order to
properly utilize the image information contained in conjugate point coordinates and the orbit information contained in
tracking data, both data types have to be evaluated in a combined adjustment process. To this end, the conventional
bundle block adjustment algorithm is supplemented by a rigorous dynamical modeling of the satellite motion to take
orbital constraints into account.
For the forthcoming Mars96 HRSC/WAOSS experiment computer simulations on point determination have been per-
formed to obtain a survey of the attainable accuracy at local, regional and global levels. Since WAOSS will image the
entire planet, a closed block covering the entire Martian surface may be processed under ideal circumstances. Because
of the extraordinary strength of the closed block and based on the complete image, orbit, attitude and ground control
information, 60 m accuracy in X, Y and Z can be achieved. Moreover, the Mars rotation parameters can be improved
up to factor 4.
The new approach was also tested with practical data. Image data of the multi-line camera MOMS-02 and TDRSS
tracking data, both acquired during the German D2 mission, were evaluated together. An empirical accuracy of 10 m
(0.7 pixel) in X, Y and Z was obtained with only 4 groups of ground control points. Thus the efficiency of the rigorous
bundle adjustment approach integrating orbital constraints has been proved with practical data. For that reason, it will
be routinely used for the MOMS-2P/PRIRODA mission to be launched in spring 1996.
1 INTRODUCTION
The most advanced camera concept for primary data ac-
quisition makes use of 3 linear CCD sensor arrays. They
offer the advantage that stereo images are acquired quasi
simultaneously. The 3 CCD-lines are imaging different ter-
rain at the same time, whereas the 3 lines image the same
terrain at different times, as the sensor platform moves.
In the last few years the 3-line camera concept has been
realized for experimental airborne as well as spaceborne
' projects and is now getting into a pre-operational stage.
The main important camera systems based on the 3-line
camera concept are:
e Monocular Electro-Optical Stereo Scanner
(MEOSS) (Lanzl 1986)
e Modular Optoelectronic Multispectral Scanner
(MOMS-02) (Seige, Meissner 1993)
e Digital Photogrammetric Assembly (DPA)
(Müller et al. 1994)
e High Resolution Stereo Camera (HRSC)
(Neukum et al. 1995)
e Wide-Angle Optoelectronic Stereo Scanner
(WAOSS) (Sandau, Bärwald 1994)
e Wide Angle Airborne Camera (WAAC)
(Eckardt 1995)
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996
e Triplet Linear Scanner (TLS) (Murai et al. 1995)
MEOSS, DPA, WAAC and TLS are airborne projects,
whereas MOMS-02, HRSC and WAOSS are designed for
spaceborne applications. À common major objective of all
projects is the realization of and the software development
for a completely digital photogrammetric processing chain
for 3-line imagery from primary data acquisition to the
generation of Digital Terrain Models (DTM) and orthoim-
age maps.
In the following a brief description of the concept of point
determination using orbital constraints is given, which is
recommended for spaceborne applications. Computer sim-
ulations on point determination have been performed to
obtain a survey of the attainable accuracy at local, re-
gional and global levels. Furthermore, results of tests with
practical spaceborne MOMS-02 imagery are presented. Fi-
nally, conclusions are drawn and an outlook is given.
2 POINT DETERMINATION USING
ORBITAL CONSTRAINTS
2.1 Background
So far orbital constraints in satellite photogrammetry have
been formulated as early as 1960 by Brown (cf. Case 1961,
Light 1980) for the construction of a lunar control network
from metric camera photographs during the Apollo mis-
