Bundle Adjustment of Spaceborne Double-Camera Push-Broom Imagers and its Application to Lroc Nac Imagery

Abstract

The TU Berlin group of the Lunar Reconnaissance Orbiter Camera (LROC) team has implemented a Bundle Adjustment (BA) forspaceborne multi-lenses line scan imagers, by rigorously modeling the geometric properties of the image acquisition. The BA wasapplied to stereo image sets of the LROC Narrow Angle Camera (NAC) and first results show, that the overall geometry of the stereomodels were significantly improved. Ray intersection accuracies of initially up to several meters were homogenized within theintegrated stereo models and improved to 0.14 m on average. The mean point error of the adjusted 3D object points was estimated bythe BA to be 0.95 m. The inclusion of available Lunar Orbiter Laser Altimeter (LOLA) shots as 3D ground control to the BA,accurately tied to the image space by an aforegoing co-registration, allowed to register the final adjusted NAC DTM to the currentlymost accurate global lunar reference frame. The BA also provides accuracy assessments of the individual LOLA tracks used for geo-reference during the adjustment, which will be useful to further assess LOLA derived products.