Opposite-side radargrammetry of Magellan synthetic aperture radar on Venus

摘要

In the early 1990s, synthetic aperture radar onboard Magellan spacecraft has imaged 54% of the Venusian surface in the opposite-side stereo configuration while only 21% in the same-side. Much of the data for the opposite-side radargrammetry (OSR) on Venus were underutilized due to higher topographic distortion than the same-side radargrammetry (SSR). In this paper, the performance and limitations of the OSR are demon-strated based on an example over Lullin impact crater, Venus. The initial stereo match points are classified into three categories; GOOD, BAD, and TOPO, and different methods are suggested for each category to improve the quality of digital elevation model. Large areas of gentle slope on Venusian volcanic plain can be suc-cessfully matched using conventional stereo-matching algorithm. Image contrast of featureless surface can be improved by enlarg-ing the master image patch at a cost of spatial resolution, while high to moderate relief regions need further treatments such as radarclinometry. Utilization of OSR is expected to provide addi-tional DEM dataset of Venus and to give flexibility for the design of future planetary SAR missions.