Combined Adjustment of MOC Stereo Imagery and MOLA Altimetry Data

Abstract

Aboard Mars Global Surveyor (MGS), the Mars Orbiter Laser Altimeter (MOLA) collects accurate laser altimetry data over the Martian surface, while the Mars Orbiter Camera (MOC) acquires high resolution images. Recent studies have found that certain systematic misregistration exists among these two types of data due to a number of causes. In this research, a combined adjustment is proposed to correct such misregistration and accurately determine ground positions. Primary participants in this process are MOLA ranges and MOLA ground points, MOC image orientation data, and tie points collected from the MOC Narrow Angle (NA) stereo images. It is shown that the combined adjustment is very beneficial when the trajectory data has a large inconsistency. The outcome is the refined MOC image orientation and refined ground positions, which are validated by the improved MOC and MOLA registration as an independent evaluation. The theoretic study shows the ground position precision of the combined adjustment varies from 28 to 178 meters, depending on the quality of the trajectory data.