COMBINED BUNDLE ADJUSTMENT OF MOC STEREO IMAGES AND MOLA 
ALTIMETRY DATA FOR PRECISE MARS TOPOGRAPHIC MAPPING 
Jong-Suk Yoon 
Jie Shan 
Geomatics Engineering, School of Civil Engineering, Purdue University 
550 Stadium Mall Dr., West Lafayette, IN 47907-2051, USA 
yoonS@ecn.purdue.edu 
Commission IV, WG IV/9 
KEY WORDS: Photogrammetry, Extraterrestrial, Calibration, Bundle, Adjustment, Satellite, DEM/DTM 
ABSTRACT: 
Launched in 1996, Mars Global Surveyor (MGS) carries two types of mapping equipments: Mars Orbiter Laser Altimeter (MOLA) 
and Mar Orbiter Camera (MOC). MOLA collects accurate laser altimetry data over the Mars surface, while MOC acquires high 
resolution images. In the process of MOLA registration to MOC images, a certain systematic shift was reported in previous studies. 
This shift may possibly be attributed to time drift when determining the MOC image orientation. To correct such mis-registration 
and obtain accurate point determination, a bundle adjustment is developed and implemented in this paper. This is a generalized 
combined adjustment for images collected by pushbroom cameras. Primary participants in this process are MOLA ground points and 
ranges, MOC image orientation data, and tie points collected on MOC stereo images. As the outcome of the bundle adjustment, we 
obtain refined MOLA ground points, ground position of tie points, refined MOC image orientation, and an accurate and consistent 
registration between MOC images and MOLA data. The refined outcome can then be used to generate local and high resolution 
digital elevation model. 
1. INTRODUCTION 
Mars topographic mapping products have been generated since 
1960's when Mars exploration started to continuously support 
future exploration plans and scientific research. Recently, 
studies about Martian topography have become more attractive 
with new developments in exploration technology. To support 
the very recent Mars Exploration Rover (MER) missions along 
with current twin rovers, Spirit and Opportunity, the 
topography of landing sites has been studied using accumulated 
data from Mariner to Viking missions and to the latest Mars 
mapping satellite, Mars Global Surveyor (MGS). This study 
proposes a bundle adjustment for precise Mars topographic 
mapping to support the landing site study for the very recent 
MER missions along with the current twin rovers. 
The primary MGS mission objectives are to collect data about 
Martian surface, atmosphere and magnetic properties and to 
build a comprehensive dataset for future mission planning 
(Albee et al., 2001). MGS mapping instruments include Mars 
Orbiter Laser Altimeter (MOLA) and Mars Orbiter Camera 
(MOC). MOLA data is considered to be the most accurate 
mapping data at present with absolute accuracy around 10 
meters vertically and around 100 meters horizontally (Kirk et al, 
2002). MOC, a linear pushbroom sensor system, provides up to 
1.4-meter high resolution images with its narrow angle (NA) 
camera and 280-meter low resolution images with its wide 
angle (WA) camera in blue and red bands. 
MGS data processing is a challenging task. Anderson and 
Parker (2002) aligned MOLA profiles to MOC images by 
empirically matching topographic features for MER landing 
sites. Ivanov and Lorre (2002) compared MOLA topography 
from MOC WA and NA stereo pairs of MER landing sites. 
They report the topography from MOC WA is consistent with 
MOLA topographic morphology. This paper will present 
combined adjustment results using high-resolution MOC 
N 
images, laser altimetry data and MGS trajectory data for precise 
Mars topographic mapping. 
Our approach can be briefly summarized as follows. As the first 
step, MOLA registration to MOC images is carried out in the 
previous research (Shan et al. 2004). It showed that the same 
MOLA points are located on different features in the MOC 
stereo images. This mis-registration is found nearly to be à 
constant shift mainly along the flight direction. Next, we 
present a bundle adjustment to improve the registration quality 
with the contribution of tie points. Additionally, credible 
MOLA ranges and MOLA ground coordinates are also included 
in the bundle adjustment. Mathematical 
measurements and a priori statistics are thoroughly presented. 
Finally, this paper evaluates bundle adjustment results. 
This research proposes a new approach to utilize altimetry data, 
trajectory data and high resolution image data for MGS 
mapping data processing. The determination of ground points 
proposed in this research is useful to provide sufficient and 
accurate ground points for high-resolution elevation model 
generation. 
2. STUDY SITES AND MGS MAPPING DATA 
MGS mapping data in this study are chosen from three 
candidate landing sites of MER missions: Eos Chasma, Gusev 
Crater and Isidis Planitia. Based on scientific researches, final 
landing sites are selected by potential scientific values for past 
liquid water activities and engineering safe landing conditions 
for MER twin rovers (Savage and Webster, 2003). Among 
these candidate landing sites, Gusev Crater is finally chosen as 
the final landing site for Spirit which is one rover of the MER 
missions launched in 2003 summer. Isidis Planitia is chosen as 
a backup landing site. 
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